At 13, after relocating to San Francisco with a friend, Archie became a newsboy, hawking newspapers. He soon became deeply involved in labor activism and the Communist Party, organizing migrant and dustbowl workers. Subsequently, he joined the International Longshoremen's Organization and began organizing waterfront workers.
In 1935 he was charged with the murder of a labor activist and acquitted, but not before spending 81 days in prison.
When the Spanish Civil War broke out in 1936, eager to fight the fascists and join his brother, (who would soon be there), Brown applied for a passport. He was denied because he was a well known radical activist.
Eventually, he stowed away on a ship to France and made it to Spain in time to join the Abraham Lincoln Brigade in the Ebro Offensive, which was fought in the waning days of the war. He spent eight months in Spain as a machine gunner.
After the war, Brown returned to the United States and resumed his work on the waterfront and with the Communist Party. In 1940, he ran for Congress under the Communist ticket—he lost.
During World War II, Brown enlisted in the U.S. Army and was involved in the Battle of the Bulge as a member of the 76th Infantry Division.
After the war, as a high ranking member of the Communist Party, Brown was forced to go into hiding for several years owing to the political climate of the Cold War. When he emerged from hiding, Brown carried on with his union work and in 1960 he was called as a hostile witness to House Un-American Activities Committee meetings in San Francisco. He read a fierce protest statement at the hearing and became involved in three days of protests, which led to scores of arrests. As a result Brown gained national attention.
In the following years he was arrested for violating a 1959 act barring Communists from serving as union officers. In 1963 he was convicted, but in 1965 the Supreme Court overturned the legislation.
Throughout the rest of his life Brown was involved in a myriad of radical activities, from protests supporting The Sandinistas of Nicaragua to opposing the Pinochet government in Chile. He died of cancer in 1990 at age 79.