James Munro

Captain Jimmy Munro was a UNIT officer who served under Brigadier Lethbridge-Stewart. He was assigned to cordoning off Oxley Woods after the second fall of Nestene meteorites and was the first to come across the TARDIS and the Third Doctor. When the story leaked to the press, he refused to answer the reporters' questions. He later helped the Doctor defeat the Nestene invasion, during which he interrogated Sam Seeley and was forced by a Nestene duplicate of Major General Scobie to hand over a Nestene meteorite. He was then part of a raid on the Auto Plastics factory that fought a squad of Autons. (TV: Spearhead from Space, PROSE: Who Killed Kennedy)

Munro later went back to the regular army. (PROSE: The Scales of Injustice) Munro again left the regular army to join UNIT Central Control in Geneva. (PROSE: The Devil Goblins from Neptune)

In an alternate timeline, Munro attained the rank of general in UNIT. (PROSE: Prisoners of the Sun)

Behind the scenes
Munro's first name was not given on-screen, only in the novels.