After surviving a Nazi POW camp where comrades were murdered by guards during an escape attempt, Frank Enley (Van Heflin), returns home from World War II. The "war hero" is respected for his fine character and good works in the California town of Santa Lisa, where he, his young wife and baby had settled after moving from the East. What his wife does not know is that Frank relocated them in an attempt to escape his past. His nemesis is Joe Parkson (Robert Ryan), once his best friend, who also lived through the ordeal, although he was left with a crippled leg. In exchange for food, Frank had alerted the Nazi camp commander to the prisoners' escape plans, thinking wrongly that the men would not be punished. Joe is determined to exact justice on Frank, whose location he has learned from a newspaper story commending Enley for his civic endeavors.
Frank's wife Edith (Janet Leigh) is completely in the dark about his past, while Joe's girlfriend Ann Sturgess (Phyllis Thaxter) knows everything about her man, but cannot dissuade him from his passion to set past wrongs right by seeing Frank dead. Frank must confront the truth that he is a coward, not a hero.
Doggedly pursued by Joe, who stalks Frank's family at their house, Frank goes into hiding, leaving his confused wife behind. At a trade convention in Los Angeles, Frank enlists a past-her-prime prostitute, Pat (Mary Astor), who introduces him to a shady lawyer and a hitman, Johnny (Berry Kroeger). Frank lures Joe into meeting him at the Santa Lisa train station, where the hitman plans to drive up and kill Joe, the gunshot muffled by the noise of the train.
After waking from a drunken binge, Frank regrets the deal and tries to warn Joe at the station. Johnny is already waiting with a gun, but before he can complete the job Frank jumps in front of the shot. Although wounded, Frank manages to grab Johnny as he speeds off in his car, causing it to crash into a lamppost. Both Johnny and Frank are killed. Joe, realizing what Frank has done, kneels by his old captain and tells the officers that he will be the one to tell Frank's wife.
Principal photography on Act of Violence took place from May 17 to mid-July 1948, with added scenes shot in late August 1948. Filming on location, included scenes at Big Bear Lake, Big Bear Valley, San Bernardino National Forest, California, along with shooting at the MGM Studios in Los Angeles. Some of the nighttime city scenes were shot in the slum neighbourhoods of Los Angeles.
Originally adapted from unpublished story by Collier Young, before he embarked on a career as an independent producer with his future wife, Ida Lupino, the film was intended to be a small indie production. Howard Duff was to be the star, but when MGM picked up the rights, Gregory Peck was to be paired with Humphrey Bogart in the leading roles. With Robert Ryan receiving notice for other films, he was "lent" by RKO Pictures for the production.Act of Violence was the third film made by Robert Ryan in 1948, following Berlin Express and Return of the Badmen.
According to MGM records, Act of Violence earned $703,000 in the US and Canada and $426,000 overseas, resulting in a loss of $637,000.
Bosley Crowther in his review for The New York Times, emphasized that it was a director's "tour de force". "For this latter asset of the picture, we have Mr. Zinnemann to thank. He has pictured, at least, a visual setting for terror and violence and he has kept the pursued and the pursuer going at a grueling pace. In the former role, Van Heflin strains and sweats impressively. As his relentless pursuer, Robert Ryan is infernally taut. Mr. Zinnemann has also extracted a tortured performance from Janet Leigh as the fearful, confused and disillusioned wife of the hunted man and he has got squalid portraits of scoundrels from Mary Astor, Berry Kroeger and Taylor Holmes."
The staff at Variety magazine gave Act of Violence a positive review. They wrote, "The grim melodrama implied by its title is fully displayed in Acts of Violence... tellingly produced and played to develop tight excitement ... The playing and direction catch plot aims and the characterizations are all topflight thesping. Heflin and Ryan deliver punchy performances that give substance to the menacing terror ... It's grim business, unrelieved by lightness, and the players belt over their assignments under Zinnemann's knowing direction. Janet Leigh points up her role as Heflin's worried but courageous wife, while Phyllis Thaxter does well by a smaller part as Ryan's girl. A standout is the brassy, blowzy femme created by Mary Astor – a woman of the streets who gives Heflin shelter during his wild flight from fate."
Film reviewer Roger Westcombe, writing for the Big House Film Society, considers Act of Violence unsettling, and wrote, "'Act of Violence' ... with a profundity, through its unsettling moral continuum, redolent not of Hollywood simplicities of good/evil but of the art one associates with Zinnemann’s European background. This contains a clue. Fred and his brother escaped their native Austria in 1938, but their parents, waiting for U.S. visas that never came, perished – separately – in concentration camps. The "survivor guilt" this awful closing engendered must resemble the emotional see-saw ride which fiction like the ethical pendulum of Act of Violence can only start to expiate."
Currently, it holds a 90% "Fresh" rating on review aggregator Rotten Tomatoes based on 10 reviews.
Fred Zinnemann was nominated for the Grand Prize of the Festival at the 1949 Cannes Film Festival for his work on Act of Violence.