Oliver Law was born in Texas in 1899. He served in the United States Army during the First World War. After six years in the forces he left to work in a cement factory. He later moved to Chicago where he drove a taxi, worked as a stevedore and ran a small restaurant.
During the Great Depression Law joined the American Communist Party and became active in the unemployment movement. This included the organization of the International Unemployment Day demonstration on 6th March 1930. During the demonstration Law, Joe Dallet, Steve Nelson and eleven other activists were arrested and badly beaten by the police. Two weeks after the beatings Law had recovered sufficiently to march with 75,000 demonstrators to demand unemployment insurance. Law also helped to organize mass protests against Benito Mussolini and the Italian invasion of Ethiopia.
In 1936 Law joined the Abraham Lincoln Battalion, a unit that volunteered to fight for the Popular Front government during the Spanish Civil War. Law arrived in Spain in January 1937 and joined the other International Brigades at Albacete.
After failing to take Madrid by frontal assault General Francisco Franco gave orders for the road that linked the city to the rest of Republican Spain to be cut. A Nationalist force of 40,000 men, including men from the Army of Africa, crossed the Jarama River on 11th February, 1937.
General José Miaja sent three International Brigades to the Jarama Valley to block the advance. Law first saw action on 27th February. He performed so well in the battle he was promoted to commander of the machine-gun company. A few weeks later he became battalion commander. It was the first time in American history that an integrated military force was led by an African-American officer.
On 6th July 1937, the Popular Front government launched a major offensive in an attempt to relieve the threat to Madrid. General Vicente Rojo sent the Republican Army to Brunete, challenging Nationalist control of the western approaches to the capital. The 80,000 Republican soldiers made good early progress but they were brought to a halt when General Francisco Franco brought up his reserves.
Fighting in hot summer weather, the Internationals suffered heavy losses. Oliver Law was killed on 9th July when he was leading his men in an attack against Mosquito Ridge.
After the war, an anti-Communist, William Herrick, claimed that Law had been murdered by his own men who objected to being led by a black man. This claim has been dismissed by Harry Fisher, the battalion runner, who took part in the offensive: "He was the first man over the top. He was in the furthest position when he was hit by a fascist bullet in the chest." David Smith, the medic who attempted to staunch the bleeding with a coagulant, also confirmed that he had been killed by the Nationalists.
Paul Robeson attempted to get a film made on the life of Law. Robeson later complained "the same money interests that block every effort to help Spain, control the Motion Picture industry, and so refuse to allow such a story."