Coogan began his acting career as an infant in both vaudeville and film, with an uncredited role in the 1917 film Skinner's Baby. As a child actor, he is best remembered for his role as Charlie Chaplin's irrascible sidekick in The Kid (1921) and for the title role in Oliver Twist by Frank Lloyd the following year. As a child star, Coogan earned as much as $4 million, but the money was taken by his mother and step-father. He sued them in 1935, but only received $126,000. The legal battle did, however, bring attention to child actors and resulted in the state of California enacting the California Child Actor's Bill, sometimes known as the Coogan Bill.
As he grew older, Coogan's popularity as an actor waned, though he had several well-publicised love affairs with leading Hollywood starlets, including a three-year marriage to Betty Grable. He left film entirely for several years, beginning in 1941, shortly before the United States entered World War II to serve as a flight officer in the Airforce. He served in Asia, and flew gliders for the transportation of Orde Wingate's Chindits in the Burma Campaign.
After the war, Coogan returned to acting, taking mostly character roles and appearing on television. His most famous TV role was as Uncle Fester in The Addams Family television series.
He died of heart disease in 1984. He was buried at Holy Cross Cemetery
He is survived by his grandson, actor Keith Coogan