Crabbe graduated from Punahou School in Honolulu, Hawaii and the University of Southern California and was inducted in the Hawaii Swimming Hall of Fame.
He starred in a number of popular films in the 1930s and 1940s. He also played the title role in the serials Flash Gordon and Buck Rogers and was only actor who has played Tarzan, Buck Rogers and Flash Gordon - the top 3 pulp fiction heroes of the 1930s. He has a star on the Hollywood Walk of Fame at 6901 Hollywood Boulevard in Hollywood, California.
In 1931, while working on That's My Boy (1932) for Columbia Pictures, he was tested by MGM for Tarzan and rejected. Paramount Pictures put him in King of the Jungle (1933) as Kaspa, the Lion Man (after a book of that title but clearly a copy of the Tarzan stories). Publicity for this film emphasized his having won the 1932 Olympic 400m freestyle and suggested a rivalry with Johnny Weissmuller. Producer Sol Lesser wanted Crabbe for an independent Tarzan the Fearless (1933), though he first had to get James Pierce to waive rights to the part already promised to him by his father-in-law, Edgar Rice Burroughs. The film was released as both a feature and a serial; most houses showed only the first serial episode, which critics panned as a badly organized feature.
Paramount put him in a number of Zane Grey westerns, then Universal Pictures gave him the lead him in very successful sci-fi serials (Flash Gordon, Buck Rogers) from 1936-40. In 1940, he began a string of Billy the Kid westerns for low-budget (very low-budget) studio PRC. After World War II, he had devoted much of his time to his swimming pool corporation and operation of a boys' camp in New York.
In 1950, he made the serials Pirates of the High Seas (1950) and King of the Congo (1952). In addition, he was very active on television in the 1950s. In 1953, he hosted a local show in New York City that featured his serials. He played the title role of the adventure series, Captain Gallant of the Foreign Legion (1955). During television's "Golden Age", he had several "meaty" lead roles on such weekly anthology series as "Kraft Theater" ("Million Dollar Rookie") and "Philco Television Playhouse" ("Cowboy for Chris") He later returned to western features to play Wyatt Earp in Badman's Country (1958) and gave a stellar performance.