"Man truly achieves his full human condition when he produces without being compelled by the physical necessity of selling himself as a commodity."— Che Guevara, Man and Socialism in Cuba 
At this stage, Guevara acquired the additional position of Finance Minister, as well as President of the National Bank. These appointments, combined with his existing position as Minister of Industries, placed Guevara at the zenith of his power, as the "virtual czar" of the Cuban economy. As a consequence of his position at the head of the central bank, it was now Guevara's duty to sign the Cuban currency, which per custom would bear his signature. Instead of using his full name, he signed the bills solely "Che". It was through this symbolic act, which horrified many in the Cuban financial sector, that Guevara signaled his distaste for money and the class distinctions it brought about. Guevara's long time friend Ricardo Rojo later remarked that "the day he signed Che on the bills, (he) literally knocked the props from under the widespread belief that money was sacred."
In an effort to eliminate social inequalities, Guevara and Cuba's new leadership had moved to swiftly transform the political and economic base of the country through nationalizing factories, banks, and businesses, while attempting to ensure affordable housing, healthcare, and employment for all Cubans. However, in order for a genuine transformation of consciousness to take root, Guevara believed that such structural changes would have to be accompanied by a conversion in people's social relations and values. Believing that the attitudes in Cuba towards race, women, individualism, and manual labor were the product of the island's outdated past, Guevara urged all individuals to view each other as equals and take on the values of what he termed "el Hombre Nuevo" (the New Man). Guevara hoped his "new man" would ultimately be "selfless and cooperative, obedient and hard working, gender-blind, incorruptible, non-materialistic, andanti-imperialist." To accomplish this, Guevara emphasized the tenants of Marxism-Leninism, and wanted to use the state to emphasize qualities such as egalitarianism and self-sacrifice, at the same time as "unity, equality, and freedom" became the new maxims. Guevara's first desired economic goal of the new man, which coincided with his aversion for wealth condensation andeconomic inequality, was to see a nation-wide elimination of material incentives in favor of moral ones. He negatively viewed capitalism as a "contest among wolves" where "one can only win at the cost of others" and thus desired to see the creation of a "new man and woman". Guevara continually stressed that a socialist economy in itself is not "worth the effort, sacrifice, and risks of war and destruction" if it ends up encouraging "greed and individual ambition at the expense of collective spirit". A primary goal of Guevara's thus became to reform "individual consciousness" and values to produce better workers and citizens. In his view, Cuba's "new man" would be able to overcome the "egotism" and "selfishness" that he loathed and discerned was uniquely characteristic of individuals incapitalist societies. To promote this concept of a "new man", the government also created a series of party-dominated institutions and mechanisms on all levels of society, which included organizations such as labor groups, youth leagues, women's groups, community centers, and houses of culture to promote state-sponsored art, music, and literature. In congruence with this, all educational, mass media, and artistic community based facilities were nationalized and utilized to instill the government's official socialistideology. In describing this new method of "development", Guevara stated:
"There is a great difference between free-enterprise development and revolutionary development. In one of them, wealth is concentrated in the hands of a fortunate few, the friends of the government, the best wheeler-dealers. In the other, wealth is the people’s patrimony."
A further integral part of fostering a sense of "unity between the individual and the mass", Guevara believed, was volunteer work and will. To display this, Guevara "led by example", working "endlessly at his ministry job, in construction, and even cutting sugar cane" on his day off. He was known for working 36 hours at a stretch, calling meetings after midnight, and eating on the run. Such behavior was emblematic of Guevara's new program of moral incentives, where each worker was now required to meet a quota and produce a certain quantity of goods. As a replacement for the pay increases abolished by Guevara, workers who exceeded their quota now only received a certificate of commendation, while workers who failed to meet their quotas were given a pay cut. Guevara unapologetically defended his personal philosophy towards motivation and work, stating:
"This is not a matter of how many pounds of meat one might be able to eat, or how many times a year someone can go to the beach, or how many ornaments from abroad one might be able to buy with his current salary. What really matters is that the individual feels more complete, with much more internal richness and much more responsibility."
In the face of a loss of commercial connections with Western states, Guevara tried to replace them with closer commercial relationships with Eastern Bloc states, visiting a number of Marxist states and signing trade agreements with them. At the end of 1960 he visitedCzechoslovakia, the Soviet Union, North Korea, Hungary and East Germany and signed, for instance, a trade agreement in East Berlinon December 17, 1960. Such agreements helped Cuba's economy to a certain degree but also had the disadvantage of a growing economic dependency on the Eastern Bloc. It was also in East Germany where Guevara met Tamara Bunke (later known as "Tania"), who was assigned as his interpreter, and who would years later join him and be killed with him in Bolivia.
Whatever the merits or demerits of Guevara’s economic principles, his programs were unsuccessful. Guevara's program of "moral incentives" for workers caused a rapid drop in productivity and a rapid rise in absenteeism. Decades later, the director of Radio MartíErnesto Betancourt, an early ally turned Castro-critic and Che's former deputy, would accuse Guevara of being "ignorant of the most elementary economic principles." In reference to the collective failings of Guevara's vision, reporter I.F. Stone who interviewed Guevara twice during this time, remarked that he was "Galahad not Robespierre", while opining that "in a sense he was, like some early saint, taking refuge in the desert. Only there could the purity of the faith be safeguarded from the unregenerate revisionism of human nature."
On April 17, 1961, 1,400 U.S.-trained Cuban exiles invaded Cuba during the Bay of Pigs Invasion. Guevara did not play a key role in the fighting, as one day before the invasion a warship carrying Marines faked an invasion off the West Coast of Pinar del Río and drew forces commanded by Guevara to that region. However, historians give him a share of credit for the victory as he was director of instruction for Cuba’s armed forces at the time. Author Tad Szulc in his explanation of the Cuban victory, assigns Guevara partial credit, stating: "The revolutionaries won because Che Guevara, as the head of the Instruction Department of the Revolutionary Armed Forces in charge of the militia training program, had done so well in preparing 200,000 men and women for war." It was also during this deployment that he suffered a bullet grazing to the cheek when his pistol fell out of its holster and accidentally discharged.
According to Dick goodwin "[Che] went on to say that he wanted to thank us [the United States] very much for the invasion –that it had been a great political victory for them– enabled them to consolidate — and transformed them from an aggrieved little country to an equal."
In August 1961, during an economic conference of the Organization of American States in Punta del Este, Uruguay, Che Guevara sent a note of "gratitude" to U.S. President John F. Kennedy through Richard N. Goodwin, a young secretary of the White House. It read "Thanks for Playa Girón (Bay of Pigs). Before the invasion, the revolution was shaky. Now it's stronger than ever." In response to U.S. Treasury SecretaryDouglas Dillon presenting the Alliance for Progress for ratification by the meeting, Guevara antagonistically attacked the United States claim of being a "democracy", stating that such a system was not compatible with "financial oligarchy, discrimination against blacks, and outrages by theKu Klux Klan". Guevara continued, speaking out against the "persecution" that in his view "drove scientists like Oppenheimer from their posts, deprived the world for years of the marvelous voice of Paul Robeson, and sent the Rosenbergs to their deaths against the protests of a shocked world." Guevara ended his remarks by insinuating that the United States was not interested in real reforms, sardonically quipping that "U.S. experts never talk about agrarian reform; they prefer a safe subject, like a better water supply. In short they seem to prepare the revolution of the toilets."
Guevara, who was practically the architect of the Soviet-Cuban relationship, then played a key role in bringing to Cuba the Soviet nuclear-armed ballistic missiles that precipitated the Cuban Missile Crisis in October 1962 and brought the world to the brink of nuclear war. A few weeks after the crisis, during an interview with the British communist newspaper the Daily Worker, Guevara was still fuming over the perceived Soviet betrayal and told correspondent Sam Russell that, if the missiles had been under Cuban control, they would have fired them off. While expounding on the incident later, Guevara reiterated that the cause of socialist liberation against global "imperialist aggression" would ultimately have been worth the possibility of "millions of atomic war victims". The missile crisis further convinced Guevara that the world's two superpowers (the United States and the Soviet Union) used Cuba as a pawn in their own global strategies. Afterward he denounced the Soviets almost as frequently as he denounced the Americans.
By December 1964, Che Guevara had emerged as a "revolutionary statesman of world stature" and thus traveled to New York City as head of the Cuban delegation to speak at the United Nations. During his impassioned address, he criticized the United Nations' inability to confront the "brutal policy of apartheid" in South Africa, asking "Can the United Nations do nothing to stop this?" Guevara then denounced the United States policy towards their black population, stating:
"Those who kill their own children and discriminate daily against them because of the color of their skin; those who let the murderers of blacks remain free, protecting them, and furthermore punishing the black population because they demand their legitimate rights as free men—how can those who do this consider themselves guardians of freedom?"
An indignant Guevara ended his speech by reciting the Second Declaration of Havana, decreeing Latin America a "family of 200 million brothers who suffer the same miseries". This "epic", Guevara declared, would be written by the "hungry Indian masses, peasants without land, exploited workers, and progressive masses". To Guevara the conflict was a struggle of masses and ideas, which would be carried forth by those "mistreated and scorned by imperialism" who were previously considered "a weak and submissive flock". With this "flock", Guevara now asserted, "Yankee monopoly capitalism" now terrifyingly saw their "gravediggers". It would be during this "hour of vindication", Guevara pronounced, that the "anonymous mass" would begin to write its own history "with its own blood" and reclaim those "rights that were laughed at by one and all for 500 years". Guevara ended his remarks to the General Assembly by hypothesizing that this "wave of anger” would "sweep the lands of Latin America" and that the labor masses who "turn the wheel of history" were now, for the first time, "awakening from the long, brutalizing sleep to which they had been subjected".
Guevara later learned that there were two failed attempts on his life by Cuban exiles during his stop at the U.N. complex. The first from Molly Gonzales who tried to break through barricades upon his arrival with a seven-inch hunting knife, and later during his address by Guillermo Novo with a timer-initiated bazooka that was fired off target from a boat in the East River at the United Nations Headquarters. Afterwards Guevara commented on both incidents, stating that "it is better to be killed by a woman with a knife than by a man with a gun", while adding with a languid wave of his cigar that the explosion had "given the whole thing more flavor".
While in New York Guevara also appeared on the CBS Sunday news program Face the Nation and met with a range of people, from U.S. Senator Eugene McCarthy to associates of Malcolm X. The latter expressed his admiration, declaring Guevara "one of the most revolutionary men in this country right now" while reading a statement from him to a crowd at the Audubon Ballroom.
On December 17 Guevara left for Paris, France, and from there embarked on a three-month world tour that included vists to the People's Republic of China, North Korea, the United Arab Republic, Egypt, Algeria, Ghana, Guinea, Mali, Dahomey, Congo-Brazzaville and Tanzania, with stops in Ireland and Prague. While in Ireland Guevara embraced his own Irish heritage, celebrating Saint Patrick's Day in Limerick City.He wrote to his father on this visit, humorously stating "I am in this green Ireland of your ancestors. When they found out, the television [station] came to ask me about the Lynch genealogy, but in case they were horse thieves or something like that, I didn't say much."
During this voyage he wrote a letter to Carlos Quijano, editor of a Uruguayan weekly, which was later retitled Socialism and Man in Cuba.Outlined in the treatise was Guevara's summons for the creation of a new consciousness, a new status of work, and a new role of the individual. He also laid out the reasoning behind his anti-capitalist sentiments, stating:
"The laws of capitalism, blind and invisible to the majority, act upon the individual without his thinking about it. He sees only the vastness of a seemingly infinite horizon before him. That is how it is painted by capitalist propagandists, who purport to draw a lesson from the example of Rockefeller—whether or not it is true—about the possibilities of success. The amount of poverty and suffering required for the emergence of a Rockefeller, and the amount of depravity that the accumulation of a fortune of such magnitude entails, are left out of the picture, and it is not always possible to make the people in general see this."
Guevara ended the essay by declaring that "the true revolutionary is guided by a great feeling of love" and beckoning on all revolutionaries to "strive every day so that this love of living humanity will be transformed into acts that serve as examples", thus becoming "a moving force". The genesis for Guevara's assertions relied on the fact that he believed the example of the Cuban Revolution was "something spiritual that would transcend all borders".