Gary Rich Burghoff (born May 24, 1943) is an American actor who is known for originating the role of Charlie Brown in the 1967 Off-Broadway musical You're a Good Man, Charlie Brown, and the character Corporal Walter Eugene "Radar" O'Reilly in the film M*A*S*H, as well as the TV series.

He gained early experience acting with the Belfry Players of Williams Bay, Wisconsin.

The group opened at the Sahara Hotel and Casino lounge in Las Vegas, Nevada, and played there for three months.

It became a group of sophisticated, highly educated doctors (and one head nurse) who would rather be anywhere else and who understood the nature of the "hellhole" they were stuck in.

With [Larry] Gelbart's help, I began to mold Radar into a more innocent, naïve character as contrast to the other characters, so that while the others might deplore the immorality and shame of war (from an intellectual and judgmental viewpoint), Radar could just REACT from a position of total innocence.

Fellow cast member Mike Farrell tried to persuade Burghoff to stay on the show, citing the lackluster careers of former M*A*S*H regulars Larry Linville and McLean Stevenson after their departures.

His focus, his ability to find those little gems of behavior that made everything absolutely true were a marvel to behold.

In the M*A*S*H episode "Showtime", Radar is seen playing a solo on the drums; he was actually performing, and the music was not overdubbed.

[14][15] Other Burghoff inventions include a toilet seat lifting handle (U.S. patent D314322) and a new type of fishing pole.