He was known for his roles as authority figures, often playing military characters or policemen in films such as The Third Man, The Blue Lamp, The Battle of the River Plate, and Whistle Down the Wind.

[2][nb 1] Edmund, an actor, introduced his six-year-old son to the stage in 1914 in a sketch called "The Double Event"[5] at the Oxford Music Hall in London.

Although Lee was in wartime service in the army between 1940 and 1946,[9] he had managed to act in several films earlier which were released between 1939 and 1943, including Murder in Soho, The Frozen Limits, and Let George Do It!

He had appeared in Murder in Soho (1939) then in Herbert Wilcox's The Courtneys of Curzon Street (1947), playing a colonel alongside Anna Neagle, Michael Wilding and Daphne Slater; the film was a major success and became the biggest hit at the British box office of 1947.

[11] He developed a reputation for playing "solid, dependable characters such as policemen, serving officers or officials"[6] in films such as The Fallen Idol (1948), The Third Man (1949), The Blue Lamp (1950), Last Holiday (1950), Cage of Gold (1950), Mr. Denning Drives North (1952), White Corridors (1951), The Yellow Balloon (1953), Beat the Devil (1953), and Father Brown (1954), and commanders, colonels, or brigadiers in films such as Morning Departure (1950), Calling Bulldog Drummond (1951), Appointment with Venus (1951), and many more.

[13] During the 1950s, Lee had a long run on stage, appearing as Able Seaman Turner in Seagulls Over Sorrento,[7] a role he later reprised in the film of the same name with Gene Kelly (released in the US as Crest of the Wave).

[14] Lee starred opposite Gregory Peck in The Purple Plain (1954), playing a Royal Air Force medical officer based in Burma during the late Second World War and portrayed Captain Patrick Dove in Michael Powell and Emeric Pressburger's war film The Battle of the River Plate (1956), based upon the battle of the same name.

In 1962 Lee was cast in the role that The Illustrated Who's Who of the Cinema described as his best remembered,[17][18] playing the character of M, the head of the Secret Intelligence Service (MI6)—and the superior of James Bond—in the first Eon Productions film, Dr. No.

[23] Terence Pettigrew, in his study British film character actors: great names and memorable moments agreed, noting that Lee was a "gruff, reliable, no-nonsense role character actor",[8] with "kindly eyes, droll manner and expressly Anglo-Saxon level-headedness".

In 1972, he portrayed Tarmut the sculptor in Terence Fisher's Hammer Horror picture Frankenstein and the Monster from Hell, alongside Peter Cushing, Shane Briant, and David Prowse; it was not released until 1974.

[25] According to the actor Jack Warner, "Bernard and Gladys had a lovely 17-century cottage in the Kent village of Oare, and it was there she died tragically in a fire early in 1972.

[38] A year after Lee's death, Terence Pettigrew summarised his acting work as a "Gruff, reliable, no-nonsense role character actor, whose many credits include policemen, servicemen, father figures, and spy chiefs.