Born Herbert Theodore Bergman in New York City, he majored in journalism at Columbia University, and then began his acting career in the city, eventually working on Broadway. He was Jewish. For a time, he continued to list himself either as Bergman or Alan Reed, depending on the role he was playing (Reed for more comedic roles, Bergman for more serious ones). He was able to act in 22 foreign dialects, and made a career as a successful radio announcer and stage actor. In 1932, Reed married the former Finette Walker (1909–2005), a Broadway actress. She appeared on stage in the early 1930s and was a chorus member in the original 1934 Broadway production of Anything Goes with Ethel Merman. They had three sons, including actor Alan Reed, Jr. (born May 10, 1936). Once his son started acting, Reed took the professional name Alan Reed, Sr. His radio work included having two roles in Valiant Lady, the role of Solomon Levy on Abie’s Irish Rose, as the “Allen’s Alley” resident poet Falstaff Openshaw on Fred Allen’s NBC radio show, and later on his own five-minute show, Falstaff’s Fables, on ABC, as Officer Clancey and other occasional roles on the NBC radio show Duffy’s Tavern, as Shrevey the driver on several years of The Shadow, as Chester Riley’s boss on the NBC radio show The Life of Riley, and as Italian immigrant Pasquale in Life with Luigi on CBS radio, and various supporting roles on Yours Truly, Johnny Dollar, also on CBS.

From 1957–58, Reed appeared in a recurring role as J.B. Hafter, a studio boss, on the CBS sitcom Mr. Adams and Eve, starring Howard Duff and Ida Lupino, then married in real life, but appearing as a fictitious acting couple living in Beverly Hills, California. In 1963, he appeared as Councilman Jack Gramby in episode 8 of the CBS sitcom My Favorite Martian. In 1964–65, he had a recurring role as Mr. Swidler in the ABC sitcom Mickey, starring Mickey Rooney as the owner of a resort hotel in Newport Beach, California. As a voice actor, Reed provided the voice of Boris the Russian Wolfhound in Walt Disney’s Lady and the Tramp in 1955. In 1960, he began the voice role for which he was most famous, that of Fred Flintstone, the lead character of Hanna-Barbera’s prime-time animated series The Flintstones. Reed provided Fred’s voice for the entire six-season run of the show, as well as in several spin-off series (The Pebbles and Bamm-Bamm Show, The Flintstone Comedy Hour) and specials. His final performance as Fred Flintstone was a cameo guest shot on an episode of Scooby’s All-Star Laff-A-Lympics. Among his other voice roles for Hanna-Barbera was Touché Turtle’s sidekick, Dum Dum. Radio playwright and director Norman Corwin cast Reed as Santa Claus in the 1969 KCET television reading of his 1938 play The Plot to Overthrow Christmas. Reed died of a heart attack in Los Angeles on June 14, 1977, two months shy of his 70th birthday. His body was donated to the Loma Linda University School of Medicine. He was survived by his wife, sons, and several grandchildren.