Robert Minor was born in San Antonio, Texas, on 15th July 15, 1884. His father was unemployed and so he was forced to leave school at fourteen. For the next few years he worked as a handyman to help support the family.
In 1904 Minor was hired as an assistant stereotypist and handyman at the San Antonio Gazette. While at the newspaper he developed an interest in drawing. He submitted some unsigned cartoons and these were published in the newspaper.
Minor admired the cartoons in the St. Louis Post-Dispatch. He moved to St. Louis and convinced its editor, Joseph Pulitzer, to employ him as an artist. While at the newspaper, Minor's doctor, who was treating him for increasing deafness, converted him to socialism and in 1907 he joined the Socialist Party of America. A fellow member of the party, Max Eastman, later recalled: "Bob Minor possessed brilliant and original gifts both as a writer and artist... He was a natural-born fanatic. I used to feel that he would string me to a lamppost with the pained gleefulness of a Torquemada if I diverged by a hair from the fixed path of the revolution."
Joseph Pulitzer, a campaigning journalist, did not object to the strong political statements that Minor made in his cartoons. By 1910, Minor was the chief cartoonist at the St. Louis Post-Dispatch and was considered by many to be the best in the country. The following year, the editor of the New York World offered to make Minor the highest paid cartoonist in the United States if he moved to his newspaper.
Minor was one of the first American cartoonists to employ grease crayon on paper. His work influenced a generation of cartoonists including Boardman Robinson, Daniel Fitzpatrick and Rollin Kirby. A socialist and supporter of woman suffrage, Minor contributed to feminist journals such as the Woman's Journal and Woman Voter.
On 22nd July, 1916, employers in San Francisco organised a march through the streets in favour of an improvement in national defence. Critics of the march such as William Jennings Bryan, claimed that the Preparedness March was being organized by financiers and factory owners who would benefit from increased spending on munitions.
During the march a bomb went off in Steuart Street Street killing six people (four more died later) and 40 were badly wounded. Two witnesses described two dark-skinned men, probably Mexicans, carrying a heavy suitcase near to where the bomb exploded. A friend of Minor's, Tom Mooney, was found guilty of the crime and sentenced to death.
A large number of people believed that Mooney and Warren Billings had been framed. Those involved in the campaign to get them released included Minor, Fremont Older, Heywood Broun, Samuel Gompers, Eugene V. Debs, Alexander Berkman and Emma Goldman. Over the next few months Minor addressed mass meetings, and wrote articles for several magazines about the case. Mooney was reprieved but was not released until 1938.
Minor was totally opposed to the First World War. At first his anti-war cartoons caused no problems as the editor, Horatio Seymour, shared Minor's views on the topic. However, Seymour eventually changed his mind and became a supporter of the Allies. Minor was ordered to produce cartoons that reflected this new policy. Minor refused and instead began contributing cartoons to the radical journal, The Masses. He also went to the Western Front where he wrote articles on the war.
After the USA declared war on the Central Powers in 1917, The Masses came under government pressure to change its policy. When it refused to do this, the journal lost its mailing privileges. In July, 1917, it was claimed by the authorities that cartoons by Art Young, Boardman Robinson and H. J. Glintenkamp and articles by Max Eastman and Floyd Dell had violated the Espionage Act. Under this act it was an offence to publish material that undermined the war effort.
The legal action that followed forced The Masses to cease publication. In April, 1918 the jury failed to agree on the guilt of the defendants. The second trial in January 1919 also ended with a hung jury. As the war was now over, it was decided not to take them to court for a third time.
After being released from prison Minor found work with the New York Call. He was sent to Europe and covered the Russian Civil War and the Spartakist Rising. While in Germany Minor was arrested and charged with spreading treasonous propaganda among British and American troops.
Minor was at first critical of the lack of democracy in Russia. He wrote that: "There is no more industrial democracy in Lenin's highly centralized institutions than in the United States Post Office". However, when Minor arrived home he published I Change My Mind a Little, and announced he was going to join the American Communist Party.
In 1920 Minor began living with Mary Heaton Vorse, a talented journalist who had worked with him on The Masses. She suffered a miscarriage in 1922 and soon afterwards Minor left her for illustrator Lydia Gibson. As a result of the trauma of these two events, Mary became addicted to alcohol. Minor and Gibson got married in 1923.
Minor worked as a cartoonist and writer for The Liberator and the Workers Monthly, the magazine of the American Communist Party. In 1924 he helped establish the Daily Worker and contributed articles and cartoons to the journal for the next twenty-five years. However, Theodore Draper has argued that Minor lost his creative abilities during this period: "A truly gifted and powerful cartoonist, he renounced art for politics... But he could not transfer his genius from art to politics. The stirring drawings were replaced by boring and banal speeches. He had none of the gifts of the natural politician, his stock in trade was limited to platitudes and slogans. The wild man, tamed, became a political hack."
On the outbreak of the Spanish Civil War Minor went to Spain and helped to organize the Abraham Lincoln Battalion, a unit that volunteered to fight for the Popular Front government. He was also the American representative to the Comintern in Spain. Sandor Voros later recalled that people like Minor became convinced that he was a "master strategist" and a "military genius". He wrote that: "He (Minor) spent his time in Spain devising military campaigns and giving unsolicited military advice to the Spanish Communist Party. At that second meeting, after listening for a whole evening to his military theories, I realized he was oblivious of the political and military developments around him and that he was becoming senile."
After the Second World War Minor became southern editor of the Daily Worker. He campaigned for Black Civil Rights and wrote several articles exposing the involvement of local white politicians in lynching.
Minor suffered a heart attack in 1948 and was bedridden during the time when fellow leaders of the American Communist Party were arrested and imprisoned.
Robert Minor died in 1952.