Gary Richard Burghoff (born May 24, 1943) is an American actor, known for playing the character Corporal Walter Eugene "Radar" O'Reilly in the MAS*H series and Charlie Brown in the 1967 Off-Broadway musical You're a Good Man, Charlie Brown.
Description above from the Wikipedia article Gary Burghoff, licensed under CC-BY-SA, full list of contributors on Wikipedia.
M*A*S*H
As Cpl. 'Radar' O'Reilly
W*A*L*T*E*R
As Walter 'Radar' O'Reilly
Casino
As Bill Taylor
Behind the Waterfall
As Mr. Connors
Making 'M*A*S*H'
As Self
Twigs
As The Priest
M*A*S*H: The Comedy That Changed Television
As Self
B.S. I Love You
As Ted
The Man in the Santa Claus Suit
As Bob Willis
The Real M*A*S*H
As Himself
Small Kill
As Fleck / Lady Esmerelda
M*A*S*H: 30th Anniversary Reunion
As Himself
Memories of M*A*S*H
As Self / Radar O'Reilly
Enlisted: The Story of 'M*A*S*H'
As Self
Daniel's Lot
As Pastor Mahoney
Altman on His Own Terms
As Self
The Good Guys
The Love Boat
As Donald Flanders
Tales of the Unexpected
As Harry Flock
Donny & Marie
As Self
Wonder Woman
As Alan
Sweepstakes
Pets: Part of the Family
M*A*S*H
As Radar O'Reilly
Dinah!
As Self
Hollywood Squares
As Self - Panelist
CHiPs
As Gary Burghoff (uncredited)
Burke's Law
As Patrick Noyes
AfterMASH
As Radar O'Reilly
Fantasy Island
As Richard C. Delaney