Egan's first stage performance was in
Charlie Girl. His first television role was as the sex-and-cinema-obsessed Seth Starkadder in a
BBC serialisation of
Cold Comfort Farm (1968). In 1969, he had come to notoriety as the acid-throwing gangster Hogarth in the controversial
Granada series
Big Breadwinner Hog. Later, he had other starring roles: as
John Everett Millais in the BBC serial
The Love School (1975); as
Oscar Wilde (the role which introduced him to American audiences) in the serial
Lillie (1978), starring
Francesca Annis as
Lillie Langtry; as Magnus Pym in the BBC dramatisation of
John le Carré's
A Perfect Spy (1987) and another
BBC sitcom,
Joint Account (1989–90). Egan played the title role in the BBC series
Prince Regent (1979), and was a sinister immortal
Knight Templar in
Michael J. Bird's BBC series
The Dark Side of the Sun (1983). Egan also played Fothergill in the television series
Reilly, Ace of Spies (1983). In 1986, he had the role of Henry Simcox in the television dramatization of
John Mortimer's
Paradise Postponed. Egan also guest-starred in episodes of
The Ruth Rendell Mysteries ("A New Lease of Death," 1991) and
A Touch of Frost ("Private Lives," 1999). Egan's other roles have included the character Michael Cochrane in the programme
The Ambassador (1998), and (on film) as the suave secret agent Meres in television spin-off
Callan (1974), and the Duke of Sutherland in
Chariots of Fire (1981). In 2007, Egan took the role of Victor in the film
Death at a Funeral. In 2009, he toured as lead Sir Hugo Latymer in
Nikolai Foster's revival of
Noël Coward's
A Song at Twilight. He is the narrator for the US and UK versions of
Forza Motorsport 3 and its sequel,
Forza Motorsport 4. In 2012, Egan first appeared as Hugh "Shrimpie" MacClare, Marquess of Flintshire, in the Christmas special episode of
ITV's Downton Abbey. For the drama's fifth series, Shrimpie became a recurring character; he also briefly appeared in series six. Later that same year, Egan appeared in
Alan Bennett's
People, alongside
Frances de la Tour, at the
National Theatre. Also in 2012, Egan narrated a new recording of
Rick Wakeman's album,
Journey to the Centre of the Earth, based on the story by
Jules Verne. In 2024, Egan appeared in the British documentary film
I Could Never Go Vegan. ==Animal rights activism==