He portrayed a mentally disturbed airline passenger in the classic disaster film Airport (1970), his final screen appearance.
[6] After this, Katharine Hepburn helped him secure a film contract with RKO Radio Pictures and he did a screen test in New York.
He followed it with The Outcasts of Poker Flat (1937), billed third after Preston Foster and Jean Muir, and Flight from Glory (1937), a Chester Morris programmer where Heflin played an alcoholic pilot.
Heflin returned to Broadway for Western Waters (1937–38) and Casey Jones (1938), the latter for the Group Theatre and directed by Elia Kazan.
He returned to Broadway where he played Macaulay Connor opposite Katharine Hepburn, Joseph Cotten and Shirley Booth in The Philadelphia Story, which ran for 417 performances from 1939 to 1940.
It led to Heflin being offered a choice character part in the Errol Flynn western Santa Fe Trail (1940) at Warners, playing a villainous gun seller.
He received a stock deal from MGM, which initially cast Heflin in supporting roles in films such as The Feminine Touch (1941) and H.M. Pulham, Esq.
[7]: 37–39 He had a part as Robert Taylor's doomed best friend in Johnny Eager (1942), which won Heflin an Academy Award for Best Supporting Actor, and was a box office success.
[7]: 42 MGM began to groom Heflin as a leading man in B movies, giving him the star role in Kid Glove Killer (1942), directed by Fred Zinnemann, and Grand Central Murder (1942).
After recuperating from injuries incurred during training, he was transferred to the Ninth Air Force as combat photographer, flying over France and Germany, before joining, with many other actors, the First Motion Picture Unit.
When Heflin returned to Hollywood, MGM lent him to Hal Wallis to star opposite Barbara Stanwyck in The Strange Love of Martha Ivers (1946).
He was in the all-star musical Till the Clouds Roll By (1946) then was loaned to Warner Bros to co star with Joan Crawford in Possessed (1947).
Back at MGM he co-starred with Lana Turner in Green Dolphin Street (1947), a big prestige film for the studio and their biggest hit of 1947.
Heflin began appearing on television on episodes of Nash Airflyte Theatre and Robert Montgomery Presents (an adaptation of Arrowsmith).
Heflin had the lead role in a Western at Universal, Tomahawk (1951) and starred in a thriller directed by Joseph Losey, The Prowler (1951).
At Universal he made a family comedy with Patricia Neal, Week-End with Father (1951), then he was an FBI man in Leo McCarey's anti-Communist My Son John (1952).
Heflin stayed at Fox to star in Black Widow (1954) and he was top billed in Warners' Battle Cry (1955) based on Leon Uris's best seller which was a major hit at the box office.
Heflin returned to Broadway to appear in a double bill of Arthur Miller's A View From the Bridge and A Memory of Two Mondays which ran for 149 performances under the direction of Martin Ritt.
Heflin appeared in a short but dramatic role as an eyewitness of Jesus' raising of Lazarus from death in the 1965 Bible film, The Greatest Story Ever Told.
[16] In February 2016, a biography, Van Heflin: A Life in Film, by Derek Sculthorpe, was published by McFarland & Company of Jefferson, North Carolina.