She signed a contract with Metro-Goldwyn-Mayer in 1933, appearing in several films for the studio–including The Stranger's Return (1933), opposite Lionel Barrymore–before landing a supporting role as Valentine de Villefort in United Artists' The Count of Monte Cristo (1934).

Beginning in the mid-1950s, Hervey transitioned to television, appearing as a guest star on Perry Mason, Honey West, and My Three Sons, the latter of which earned her a Primetime Emmy Award nomination for Outstanding Single Performance by an Actress in a Supporting Role.

Hervey appeared in occasional minor film roles in her later career, such as Gene Saks's Cactus Flower (1969) and Clint Eastwood's thriller Play Misty for Me (1971).

Throughout the 1950s and early 1960s, Hervey appeared in several television series, including the crime dramas Richard Diamond, Private Detective, Peter Gunn, and Hawaiian Eye.

She returned to theater with a role opposite Hans Conried in Take Her, She's Mine, a comedy written by Henry and Phoebe Ephron, which had regional performances in Massachusetts and Connecticut in the summer of 1963.

[12] In 1965, she landed a regular role on The Young Marrieds, followed by a stint on the short-lived Anne Francis series Honey West as the titular character's Aunt Meg.

In 1981, she made her last on-screen appearance in the television movie Goliath Awaits, which centers on a community of survivors from a World War II shipwreck who have survived decades living underwater.

[6][9] Hervey died of heart failure on December 20, 1998; she was 89[17] and was residing at the Motion Picture & Television Country House and Hospital in Woodland Hills, Los Angeles.