Biografia

Served in the US Navy from 1938-41, then joined the Merchant Marine as water tender in the engine room but disliked convoy duty because of Axis aircraft attacks and his location three decks below the main deck--this, as he says, ended his "romance with the life of a sailor". He left the Merchant Marine in 1942, joined the US Army and became a platoon sergeant and parachute jump master in the 101st Airborne. Fought in the Battle of the Bulge. While hospitalized with a leg injury sustained in a jump, he read a play written by Clifford Odets and decided to become an actor.

Boxed as a welterweight under the name "Johnny Costello" in his youth. Fought on the same card as Charles Durning in Madison Square Garden.

He and Gilbert Gottfried are the only two actors to appear in all three "Problem Child" films. Unlike Gottfried, Warden did not participate in the animated series.

Appeared in five films that were nominated for the Academy Award for Best Picture: Da qui all'eternità (1953), La parola ai giurati (1957), Tutti gli uomini del presidente (1976), Il paradiso può attendere (1978) and Il verdetto (1982). Of those, Da qui all'eternità (1953) was the only one to win the award.

Separated from wife Wanda Ottoni some time in the mid-1970s. However, they never got divorced and were still legally married at the time of his death.