Wilford Brimley, a portly actor with a walrus mustache who found his niche playing cantankerous coots in “Absence of Malice,” “The Natural,” “Cocoon” and other films, died on Saturday in a hospital in St. George, Utah. He was 85.

He had been sick for two months with a kidney ailment, his agent, Lynda Bensky, said.

Mr. Brimley had played the Walton Mountain resident Horace Brimley in a recurring role on the television series “The Waltons” when Michael Douglas, the producer of “The China Syndrome,” gave him his breakthrough role: Ted Spindler, an assistant engineer at a nuclear plant.

In the film’s climactic scene, in which he is being interviewed by a crusading television reporter played by Jane Fonda, Mr. Brimley delivered an impassioned defense of his boss (Jack Lemmon), who had precipitated a crisis to draw public attention to defects at the plant.

In an article for The New York Times singling out Mr. Brimley as a talent to watch, Janet Maslin called him “the mustachioed man who very nearly steals the ending of ‘China Syndrome’ from Jane Fonda.”

Mr. Brimley followed up with a small but memorable performance as a pugnacious assistant U.S. attorney in “Absence of Malice” and with supporting roles in “The Natural,” as the put-upon manager of a losing baseball team, and “The Firm,” in which he played the sinister head of security at an unsavory law firm.

In Ron Howard’s 1985 fantasy film “Cocoon,” Mr. Brimley delivered one of his most engaging performances, as a Florida retiree who, with Don Ameche and Hume Cronyn, regains his youth after swimming in a magic pool.

“Wilford’s a testy guy, not an easy guy to work with all the time, but he has great instincts,” Mr. Howard told The Times in 1985. “Many of his scenes were totally improvised.”