Wallach appeared in movies such as How the West was Won, The Magnificent Seven and The Misfits.
However, he is perhaps best known for the role of Tuco in The Good, the Bad and the Ugly — the spaghetti western directed by Italian Sergio Leone — where he acted alongside Clint Eastwood.
"As an actor I've played more bandits, thieves, warlords, molesters and mafioso than you could shake a stick at," Wallach said in 2010, accepting an honorary Academy Award. Despite his acclaimed work, the actor had never been nominated for an Oscar before then.
Wallach also worked in TV, including roles on Playhouse 90 (1958-1959), Batman(1967) and Kojak (1975), and in theater. He won a Tony Award in 1951 for his starring role in Tennessee Williams' The Rose Tattoo, opposite Maureen Stapleton.
"For actors, movies are a means to an end," Wallach told The New York Times in 1973 about his love of the stage. "I go and get on a horse in Spain for 10 weeks, and I have enough cushion to come back and do a play."
He continued acting in his later years, appearing in 2006's The Holiday, 2009's Tickling Leo and 2010's Wall Street: Money Never Sleeps, among other small film and TV roles.