He appeared in pictures such as Western Jamboree (1938) with Gene Autry, The Best Years of Our Lives (1946) with Fredric March and Myrna Loy, The Black Arrow (1948), Billy Wilder's Ace in the Hole (1951) and Judgment at Nuremberg (1961) with Spencer Tracy and Burt Lancaster.

After more than 15 years performing in films and in early television, Teal secured a recurring role as a police officer in the 1953–1955 ABC sitcom with a variety-show theme, Where's Raymond?, later renamed The Ray Bolger Show.

In 1957, Teal played a lawman, Captain McNelly, in the episode "Sam Bass" of NBC's Tales of Wells Fargo.

On the Warner Bros. series Maverick starring James Garner and Jack Kelly, Teal played a crooked sheriff in the episode "The Day They Hanged Bret Maverick" (1958) and also starred as villains in the episodes "Stage West" (1957) based on a story by Louis L'amour and "Two Beggars on Horseback" (1958).

In 1960, Teal was cast as Sheriff Roy Coffee in Bonanza, a role he played until 1972, appearing in 98 episodes, occasionally as the lead character.

In 1962, Teal portrayed Mr. Todd in the episode entitled "The Tall Shadow" of the NBC modern Western drama, Empire.

In 1963, Teal appeared as murder victim Joe Downing in the CBS courtroom drama series Perry Mason episode, "The Case of the Shifty Shoebox".

Notable film roles include playing one of the judges in Judgment at Nuremberg (1961) with Spencer Tracy and an indulgent bar owner to Marlon Brando's motorcycle gang in The Wild One (1953).