He is most famous for his roles as the bumbling and well-meaning Tom in the 1994 British romantic comedy film Four Weddings and a Funeral and the dim-witted but kind-hearted Hugo Horton in the BBC sitcom television series The Vicar of Dibley.
[6][7][8] He has since appeared in touring productions of, among others, Habeas Corpus[9] and In the Club,[10] as well as in Festen and Mary Stuart[11] and others in the West End.
Between 2000 and 2006, Fleet played the painfully upright and decent Captain Brimshaw in Revolting People, a BBC Radio 4 comedy set in pre-revolutionary America.
He also plays the part of Sir John Woodstock in the BBC Radio 4 sitcom The Castle and Inspector Lestrade in the first, third and fourth series of The Rivals.
Earlier in his career, Fleet was seen in a 1983 episode of Grange Hill as a teacher at the eponymous school's upmarket rival Rodney Bennett.
He played a character called Robbie Sloan, a recently released convict, helping escaped prisoner Tony Gordon plot revenge on his ex-wife Carla Connor.
Leaving her tied to a chair with her mouth taped shut, Sloan also lures Hayley Cropper into the hostage situation.
In September 2014, Fleet appeared in the BBC Three sitcom Bad Education as Richard, an ex-boyfriend of Rosie Gulliver.
In 2013, Fleet was engaged to play Scottish historian, the Reverend Dr. Reginald Wakefield, in seasons 1 and 2 of the Award-winning Starz adaptation of Diana Gabaldon's Outlander, broadcast in 2014–2016.
An April 2021 announcement stated that Fleet would be joining the cast of the second season of All Creatures Great and Small in the role of Colonel Merrick.
Fleet lives in Sibford Gower, Oxfordshire with his wife, actress Jane Booker, and their son Hamish.