Tom Bosley, a warm-voiced, round-bodied actor who personified paternal authority, especially on Broadway as a big-city mayor in the musical “Fiorello!” and on television as a Middle American dad in the hit comedy “Happy Days,” died Tuesday in Rancho Mirage, Calif. He was 83.

The cause was cancer, according to a statement by CBS Films, whose president, Amy Baer, is Mr. Bosley’s daughter.

Mr. Bosley is probably best known for his decade, beginning in 1974, as Howard Cunningham, the gruff but reliably kind father of teenage children in 1950s Milwaukee in the nostalgic situation comedy “Happy Days.” He also had significant roles on popular crime-solving dramas, including the title character in “The Father Dowling Mysteries” and Sheriff Amos Tupper, an ally of the sleuth and mystery writer Jessica Fletcher (Angela Lansbury), in “Murder, She Wrote.”

But before he was a television fixture, Mr. Bosley had gained fame on stage, playing Fiorello La Guardia, the populist mayor of New York, in “Fiorello!” The show won the Pulitzer Prize, and Mr. Bosley, a newcomer to Broadway, won a Tony Award for best featured actor in a musical. He never missed one of the show’s almost 800 performances.

In his review of the show in The New York Times, Brooks Atkinson summarized the appeal that Mr. Bosley would have for audiences for decades to come. Mayor La Guardia, Atkinson wrote, “is extremely well-played by Tom Bosley, who is short and a trifle portly, has a kindly face, abundant energy and an explosive personality.”

Thomas Edward Bosley was born in Chicago on Oct. 1, 1927. His father, Benjamin, worked in real estate; his mother, Dora, was a concert pianist before giving up her musical career to raise two sons. The family suffered through the Depression, and after high school, near the end of World War II, young Tom joined the Navy. He took up acting in a serious way after his discharge.

In an interview in 2000 with the Archive of American Television, he said that before he left Chicago in 1950, he flipped a coin to decide whether to move to New York or Los Angeles. The coin came up in favor of Los Angeles. But he demurred.

“I looked in the mirror and said, ‘I think I better go to New York and work in the theater,’ ” he said. “Because I was short, kind of heavy, and that is not the way to break into the film industry.”

In the 1950s, Mr. Bosley studied briefly (and unhappily) with Lee Strasberg and worked in small theaters and in television dramas, notably “Hallmark Hall of Fame” productions like “Born Yesterday” and “Alice in Wonderland.” To pay the rent, he was a hat checker at Lindy’s and a doorman at Tavern on the Green.

After “Fiorello!” work came easier. He appeared in several more Broadway shows in the 1960s, and though none were especially successful, after a long hiatus he returned to Broadway in 1994 as Belle’s father in the original cast of the Disney musical “Beauty and the Beast.”

Mr. Bosley’s fatherly appeal was suited to both comedy and drama, and his long résumé as a character actor in the movies stretched across generations of stars, beginning with “Love With the Proper Stranger” (1963) with Natalie Wood and Steve McQueen and “The World of Henry Orient” (1964) with Peter Sellers and continuing through this year, when he appeared in the romantic comedy “The Back-up Plan” with Jennifer Lopez.

He also made appearances in myriad television series, including “Ben Casey,” “Dr. Kildare,” “Get Smart,” “Mission: Impossible,” “The Mod Squad,” “Bonanza” and “Bewitched.”

In “Happy Days,” which was initially set during the mid-1950s but moved into the ’60s in its 11-season run, Mr. Bosley played a grumbly sweetheart of a husband to his wife Marion (Marion Ross) and an unconvincingly stern but wise and understanding father to his children, two of them played by Ron Howard (Richie) and Erin Moran (Joanie).

Howard Cunningham owned a hardware store, was often seen reading the newspaper in his easy chair and was perpetually befuddled by the behavior of young people. With its mix of cornball humor and family values, the series became a situation comedy landmark, spawning spinoffs and making celebrities of the cast, especially Henry Winkler, who played Richie’s charismatic, sweetly renegade friend Arthur Fonzarelli, a k a the Fonz, who referred saucily to Mr. Bosley’s character as Mr. C.

In 2004 Mr. Bosley was listed at No. 9 on TV Guide’s list of the greatest TV dads of all time.

Mr. Bosley’s first marriage, to Jean Eliot, ended with her death in 1978. In addition to his daughter, he is survived by his wife, the former Patricia Carr, whom he married in 1980; a brother, Richard; two stepdaughters, Kimberly diBonaventura and Jamie Van Meter; and seven grandchildren.

In the interview with the television archive, Mr. Bosley said he had suffered stage fright only once. It was very early in his career, before he moved to New York, and he had a small role in a play outside of Chicago that starred Shelley Berman and Geraldine Page. At the first performance, he was obsessively going over his lines backstage and lost track of the progress of the play. He made his entrance several minutes early.

“And Shelley Berman is on one side of the stage, and Geraldine Page is on the other side,” he recalled. “And she turns and looks at me and says, ‘Do you mind? We’re doing a play here.’ ”