Glover's well-known film roles have included playing villains in several major motion picture franchises: General Maximilian Veers in The Empire Strikes Back (1980), Aristotle Kristatos in For Your Eyes Only (1981), and Walter Donovan in Indiana Jones and the Last Crusade (1989).

He played the recurring supporting role of Grand Maester Pycelle in HBO's Game of Thrones (2011–2016) and appeared as General Beauvilliers in the BBC drama Spies of Warsaw (2013).

[6] He also appeared twice in Doctor Who: as Richard the Lionheart in The Crusade (1965);[7] and as the villain Scaroth, last of the Jagaroth, in one of the original run's most popular serials, City of Death (1979).

In the 1980s, Glover made some of his most notable appearances: the Imperial general Maximilian Veers in The Empire Strikes Back (1980),[9] the ruthless Greek villain Aristotle Kristatos in the James Bond film For Your Eyes Only (1981) and the deceptive American Nazi collaborator Walter Donovan in Indiana Jones and the Last Crusade (1989).

[10] On television, he played the leading role of Sir Martin Lacey in the BBC English Civil War drama series By the Sword Divided,[11] and played the guest role of surgeon Arnold Richardson in a 1989 episode of the BBC medical drama Casualty (he made a second guest appearance as a different character in 2011, and also appeared as a different character again in the sister series Holby City in 2014).

[16] Glover portrayed the character of Grand Maester Pycelle in the HBO series Game of Thrones between 2011 and 2016, appearing in a total of 31 episodes across the first six seasons of the show.

In the same year, he portrayed an old man in horror thriller Backtrack[20] as well as a theater performance as The Interlocutor in the 2014 West End transfer of the Scottsboro Boys in October.

[26] In 2020, Glover sold 250 lots of photographs, costumes, props and memorabilia from his career at East Bristol Auctions, including his badge of rank from The Empire Strikes Back and the watch, overcoat and personal script from Indiana Jones and the Last Crusade.