McNally's first professional acting work, at age 16, was at the
Birmingham Repertory Theatre. In 1973 he received a scholarship to attend the
Royal Academy of Dramatic Art where, in 1975, he won the Best Actor Bancroft Gold Medal. In 1976, he appeared in BBC's
I, Claudius and, in 1977, was a regular in the second series of
Poldark playing Drake Carne, younger brother of Demelza Poldark. From 1991 to 1994, he wrote nine episodes of
Minder, under the pseudonym Kevin Sperring, with writing partner Bernard Dempsey. He also wrote two episodes of
Boon, and two episodes of
Lock, Stock with Dempsey. McNally played
Joshamee Gibbs in the
Pirates of the Caribbean films. He is one of only three actors who appear in all five films, and reprised the role in
Kingdom Hearts III, making him the only actor from the film series to reprise a role in
Kingdom Hearts. He also reprised the role in 2021 for
Sea of Thieves' "A Pirate's Life" Tall Tale series. Along with fellow British actors
Ian McNeice and
Kenneth Branagh, McNally appeared in two
Second World War films,
Valkyrie and
Conspiracy, that depict behind the scenes activities of high-ranking officials in
Nazi Germany. In 2011, he was cast in the American television series
Supernatural as Frank. In 2012, he performed as a voice actor for the best selling videogame ''
Assassin's Creed III, providing the likeness and voice of the character of Robert Faulkner. In 2013, he began working on a science-fiction animation project, Starship Goldfish''. In 2014, he played the lead role in re-recorded radio plays of five lost episodes of ''
Hancock's Half Hour for BBC Radio 4. Following this, a further video episode was re-recorded and broadcast on BBC Four as part of the Lost Sitcoms'' series. From 2014 to 2017, McNally played Judge Richard Woodhull of Setauket, Long Island, in the
AMC series ''
Turn: Washington's Spies''. In July 2019, he guest-starred as Inspector Grandjean in Season 2, Episode 1 of
Amazon's mystery series
Maigret. In 2019, McNally portrayed
Captain Mainwaring in a series of
re-enactments of otherwise lost episodes of the sitcom ''
Dad's Army''. In 2021, McNally appeared in three episodes of
Flux,
Doctor Whos thirteenth series, as Professor Jericho, quickly becoming a fan-favourite character. McNally previously appeared in
Doctor Who in the 1984 serial
The Twin Dilemma as Lieutenant Hugo Lang. ==Personal life==