Barratt was born on July 10, 1891^[1] in New York City, and educated in the public schools there. He left college and home during his sophomore year, traveling on a tramp steamer to Central America, England, France, and South America. After he returned to the United States, he worked for two years on his brother's farm near Springfield, Massachusetts, until he learned of an opening in the chorus for a musical comedy.^[2]

Early in his career, Barrat traveled around the United States,^[2] sometimes acting with stock theater companies and sometimes performing in vaudeville on the Keith and Orpheum circuits. Returning to New York City, he had a role in The Weavers at the Garden Theatre.

Barrat acted on Broadway, where his credits include Lilly Turner (1932), Bulls, Bears and Asses (1931), This Is New York (1930), Judas (1928), The Lady Lies (1928), A Lady for a Night (1927), Marco Millions (1927), Chicago (1926), Kid Boots (1923), The Breaking Point (1923), The Unwritten Chapter (1920), The Crimson Alibi (1919), The Invisible Foe (1918), and Some One in the House (1918).^[3]

Barrat appeared in around 150 films, uncredited in some of them, in a Hollywood career that lasted four decades. He appeared in seven pictures with James Cagney during the 1930s. He played Nick, the sexually abusive father of Barbara Stanwyck's character, Lily, in the Pre-Code classic Baby Face.

Two of his most noted roles were as the murder victim Archer Coe in Michael Curtiz's The Kennel Murder Case (1933) and as the treacherous Major Ferdinand Walsin Esterhazy in the 1937 Academy Award-winning film The Life of Emile Zola. He played several other historical characters as well, among them Davy Crockett in Man of Conquest, Zachary Taylor in Distant Drums, Abraham Lincoln in Trailin' West, Cornelius Van Horne in Canadian Pacific and General Douglas MacArthur twice,^[4] in They Were Expendable and American Guerrilla in the Philippines. He also appeared with the Marx Brothers in Go West (1940).

In the mid-1950s, Barrat transitioned to television roles. His final acting appearance was in an episode of The Alfred Hitchcock Hour in 1964.

He died of a heart ailment in Hollywood in 1970, aged 78.^[4] He was survived by his wife, Mary Dean.^[4] He was buried at Green Hill Cemetery, Martinsburg, West Virginia.^[5]

• Robert Barrat at IMDb
• Robert Barrat at the Internet Broadway Database