Her husband, critic and screenwriter Jay Cocks, said the cause was complications of dementia.

While “Animal House” was probably her best-known role, “Medium Cool” offered Bloom an auspicious beginning.

She had been acting mostly onstage when a small role in Studs Terkel’s play “Amazing Grace” led Turkel to recommend her for “Medium Cool” (1969), cinematographer Haskell Wexler’s first feature as a director.

Shot in cinéma vérité style, “Medium Cool” is the story of a local news cameraman (Robert Forster) who meets Eileen (Bloom), a poor woman from West Virginia raising her teenage son in Chicago, while covering the city’s social unrest.

Blending actual events with a fictional story, Wexler filmed Bloom — dressed in an easily seen canary yellow dress — walking through Grant Park, hoping to find her son while encountering demonstrators who had been bloodied and tear-gassed by police officers.

Wexler conceded that it had been cruel to send Bloom into peril. Cocks recalled Wexler’s telling him after the filming that he had not wanted her to return to the melee after the first day of shooting but that she had insisted on continuing.

“Sure, I felt the sense of danger,” she said in an interview in 1969. “But I tried to stay on the fringe of it, to get away from the trouble.”

Bloom followed “Medium Cool” with several prominent screen roles, including one opposite Clint Eastwood in his western “High Plains Drifter” (1973), and another as Frank Sinatra’s wife in the made-for-television detective movie “Contract on Cherry Street” (1977).

But few of her roles resonated like Marion Wormer, the boozy wife of Dean Vernon Wormer in “Animal House,” the raunchy hit comedy about the reprobates of a fraternity house at fictional Faber College. Directed by John Landis, it had a cast featuring John Belushi, Donald Sutherland, Karen Allen, Tom Hulce and Tim Matheson.

In her first scene with Otter (Matheson), the suave leader of the frat, Bloom established her identity.

Otter is clumsily trying to seduce her in a supermarket produce aisle by talking about cucumbers. “My name is Eric Stratton,” Matheson says. “They call me Otter.”

“My name’s Marion,” Bloom says. “They call me Mrs. Wormer.”

“We have a Dean Wormer at Faber.”

“What a coincidence,” she replies, puncturing his confidence. “I have a husband named Dean Wormer at Faber.”

She later shows up a frat house toga party and ends up in bed with the young man.

Matheson recalled in a telephone interview that Bloom “didn’t look down at what we were doing and jumped right in.”

He added: “I was already in awe of her because I’d loved her in ‘Medium Cool’ and ‘High Plains Drifter.’ Here was this serious, accomplished dramatic actress doing our silly little movie. Her commitment was just remarkable. She was fearless.”

Verna Frances Bloom was born Aug. 7, 1938, in Lynn, Massachusetts. Her father, Milton, owned a grocery store, and her mother, Sara (Damsky) Bloom, was a homemaker. When the couple divorced, she took over the store. She later became a bookkeeper for a trucking firm.

Bloom began acting after receiving a bachelor’s degree in fine arts at Boston University. With her first husband, Richard Collier, she started a repertory theater in Denver in the early 1960s.

But within a few years she was divorced and in New York, working in the box office at the Martin Beck Theater during the Broadway run of Peter Weiss’ “Marat/Sade,” which had been a sensation in London. It takes place in the bathhouse of an insane asylum in France, where the Marquis de Sade, an inmate, stages a play for the other inmates.

Bloom watched the play, which starred Glenda Jackson, over and over. In 1967, when “Marat/Sade” was revived on Broadway, Bloom was cast in the role that Jackson had played.

In his review for The Associated Press, William Glover wrote that Bloom “scores with touching grace as a lyrical Charlotte Corday.”

She did not return to Broadway until the 1980s, when she was cast in Neil Simon’s “Brighton Beach Memoirs” — one of a number of actresses who succeeded Joyce Van Patten as Blanche Morton, the widowed aunt of the lead character.

In addition to Cocks, Bloom is survived by her son, Sam Cocks.

Bloom’s final movie role was as Mary, Mother of Jesus, in Martin Scorsese’s “The Last Temptation of Christ” (1988). Fifteen years later, she played the stepmother of White House press secretary C.J. Cregg (Allison Janney) in an episode of “The West Wing.” It was her final television appearance.

She did not find good roles forthcoming, and Cocks said she had chosen to focus on raising their son.

He said the western “The Hired Hand” (1971), Peter Fonda’s directorial debut, provided Bloom with her most fulfilling character: Hannah, who had been abandoned by her drifter husband (Fonda) years earlier but welcomes him back reluctantly because he has agreed to be her hired help.

“It was about a very independent, strong, sensual, vulnerable demanding woman,” Cocks said. “A lot of her was in that role.”

This article originally appeared in The New York Times.