William Shatner matches all the clues, but the picture doesn't look like him. I'll go with him.
Correct, that is Shatner just after the war when he was a teen. Before he got his big break on Star Trek he acted several times with Nimoy, Doohan and DeForest on other productions. He was on these production with the following actors :
He was on Howdy doody
The Verdict Was Treason
Episode aired Apr 3, 1955
With Patrick Macnee
Goodyear Playhouse
All Summer Long
Episode aired Oct 28, 1956
With Raymond Massey
The Kaiser Aluminum Hour
Mr. Finchley Versus the Bomb
Episode aired Sep 25, 1956
With Cloris Leachman
Omnibus
Oedipus, the King
Episode aired Jan 6, 1957
With Christopher Plummer
Studio One
No Deadly Medicine: Part 2
Episode aired Dec 16, 1957
With Bea Arthur Charles Bronson Lee J. Cobb
Studio One
The Defender: Part 2
Episode aired Mar 4, 1957
With Steve McQueen
The Brothers Karamazov
1958
With Yul Brynner
Suspicion
TV Series
1957–1958
With Jack Klugman
Climax!
TV Series
1954–1958
With Peter Lorre
Playhouse 90
TV Series
1956–1961
With James Mason
Alfred Hitchcock Presents
Road Hog
Episode aired Dec 6, 1959
With Richard Chamberlain
Encounter
TV Series
1952–1961
With Bruno Gerussi Lorne Greene
The Grim Reaper
Episode aired Jun 13, 1961
With Boris Karloff
Judgment at Nuremberg
1961
With Burt Lancaster Marlene Dietrich Judy Garland Spencer Tracy
77 Sunset Strip
5: The Conclusion
Episode aired Oct 18, 1963
With William Conrad
Channing
TV Series
1963–1964
With James Caan Peter Fonda
Alexander the Great
TV Movie
1963
With Adam West
Arrest and Trial
TV Series
1963–1964
With Chuck Connors
The Outrage
1964
With Edward G. Robinson Paul Newman
A Competent Witness
Episode aired May 9, 1965
With Al Waxman
Bob Hope Presents the Chrysler Theatre
Wind Fever
Episode aired Mar 2, 1966
With Keye Luke
Dr. Kildare
Out of a Concrete Tower
Episode aired Mar 8, 1966
With Jack Nicholson