Thomason first began appearing in movies in often uncredited small roles in the late 1940's following military service during World War II. Blessed with a distinguished face and manner as well as usually sporting a neatly trimmed moustache, Reg was frequently cast as gentleman in pubs, clubs, or restaurants, government officials, and military officers. He was married to his wife Ruby Rosemary Cannings from 1940 to 2002. Reg continued to act in both films and TV shows alike up until the early 1990's – over 100 appearances in total.
One of his first appearances was in an uncredited role in Passport to Pimlico – he played the role of a member of the audience (pictured) in the cinema scene.
Just a few of the films that he appeared in include: No Orchids for Miss Blandish 1948, Cloudburst 1951, The One That Got Away 1957, A Night To Remember 1958, I was Monty’s Double 1958, Piccadilly Third Stop 1960, The Mouse on the Moon 1963, A Touch of Love 1969 and at least nine Carry on Films – Carry on Sergeant 1958 (pictured) Carry On Nurse 1959, Carry on Constable 1960, Carry on Cruising 1962, Carry on Jack 1963 plus several others.
His TV career saw him appearing in Blakes Seven, Jeeves and Wooster and Mrs Dalloway 1997.
Thomason died on August 30, 2003 in London, England.