His roles for Hammer Studios during the 1950s and '60s included the Baron's assistant in The Revenge of Frankenstein (1958), and as the dashing heroes of Dracula, Prince of Darkness and Rasputin, the Mad Monk (both 1965).
On television he played Francis Durbridge's amateur sleuth Paul Temple in the series of the same name between 1969-71, with Ros Drinkwater as Temple's wife Steve. The series proved so popular in West Germany that later series were co-productions between the BBC and Munich's Taurus films.
Matthews not only appeared with Morecambe and Wise in The Intelligence Men (1965) and That Riviera Touch (1966) - forging a close friendship with Morecambe - but also appeared throughout the 1960s and 1970s in a variety of comedy roles. He appeared on The Morecambe and Wise Christmas Show in 1977. He starred alongside George Cole in Charles Woods' highly regarded TV sitcom Don't Forget To Write (1977) as a successful writer.
In 1967, Matthews provided the voice of Captain Scarlet in the Gerry and Sylvia Anderson television series. In the late 1970s he was the narrator and host in the BBC-produced English crash course Follow Me!, which has been broadcast all over the world (though very little in the UK). In 1983 over 100 million people in China used this series to learn English.
In 2000 Matthews and his wife Angela Browne appeared in two Ray Cooney plays on the cruise ship Marco Polo which cruised to the Antarctic: Run For Your Wife and Funny Money.
He has continued to appear on the small screen into the 21st century.