Biography
Gary Fred Merrill (August 2, 1915 – March 5, 1990) was an American film and television character actor whose credits included more than fifty feature films, a half-dozen mostly short-lived TV series, and dozens of television guest appearances. Description above from the Wikipedia article Gary Merrill, licensed under CC-BY-SA, full list of contributors on Wikipedia.
Known For

Phone Call from a Strange...
David Trask

All About Eve
Bill Sampson

Mysterious Island
Gideon Spilitt

Clambake
Sam Burton

Twelve O'Clock High
Colonel Keith Davenport

Where the Sidewalk Ends
Tommy Scalise

A Blueprint for Murder
Fred Sargent

Huckleberry Finn
Pap

This Is the Army
Backstage MP on Right (uncredited)

The Missouri Traveler
Doyle Magee