Scarfe was born in Harpenden, England, the son of Gladys Ellen (née Hunt) and Neville Vincent Scarfe, both university professors. Neville Scarfe was the Founding Dean of the Faculty of Education at UBC and served in that position from 1956-1973. Alan has a son named Jonathan Scarfe who is also an actor and director. He has been married to Barbara March since 1979 and they have a daughter named Antonia (Tosia) Scarfe who is a musician and composer. Jonathan and Tosia collaborated on the short film Speak, Jonathan as director, Tosia as composer and performer of the title song, which won the Grand Jury Prize in the Short Category at Dances with Films in Los Angeles in 2001. He has two brothers; Colin Scarfe who was a professor of astronomy at the University of Victoria, and Brian Scarfe, who was a professor of economics at the University of Manitoba, University of Alberta, University of Regina, a senior university administrator at Alberta and Regina, and an Economics Consultant.
He trained at the London Academy of Music and Dramatic Art (1964–66) and began his career as a classical stage actor. He has performed well over 100 major roles in theatres across Europe (London, Liverpool, Coventry, Paris, Lille, Copenhagen, The Hague, Madrid, Warsaw, Kraków, Moscow and St. Petersburg), Canada (eight seasons at the Stratford Festival, 1972-3, 1976-9, 1985, 1992, two seasons at the Shaw Festival, 1970, 1974, as well as Vancouver, Calgary, Toronto, Montreal and Halifax) and the United States (New York, Boston, New Haven, Stamford, Philadelphia, Seattle, Dallas and Los Angeles), including King Lear, Othello, Hamlet, Iago, Brutus, Cassius, Petruchio, Prospero, Cyrano de Bergerac, Doctor Faustus, Luther, Uncle Vanya, Verlaine, John Barrymore in Sheldon Rosen's Ned and Jack and Harras in Zuckmayer's The Devil's General. He is also a stage director whose productions have ranged from the works of Shakespeare to Albee, Brecht, Beckett, Arthur Miller, Harold Pinter, Yevgeny Schwarz and Preston Jones.
He has also been a familiar face on television and film for more than forty years. He played NSA member Dr. Bradley Talmadge, the director of the Backstep Project operations, on the UPN series Seven Days. He also had guest roles as two separate Romulan characters in Star Trek: The Next Generation and as Magistrate Augris in the Star Trek: Voyager episode "Resistance". In 2003 he co-starred with his son Jonathan in Burn: The Robert Wraight Story.
After returning to Canada from Los Angeles in 2002, he began writing novels under the pseudonym Clanash Farjeon (an anagram of his full name). The titles include A Handbook for Attendants on the Insane: the Autobiography of Jack the Ripper as Revealed to Clanash Farjeon (which has been called 'one of the finest books on historical crime ever published'), The Vampires of Ciudad Juarez, about the hypocrisy of the War on Drugs and the tragedy of 'las desaparecidas', The Vampires of 9/11, a political satire about America's blindness and inability to accept who the real culprits are, and the third book of the trilogy Vampires of the Holy Spirit completes the story in Rome during April 2005, the beginning of the papacy of Joseph Ratzinger. The first three can also be found in Italian (originally published by Gargoyle Books in Rome which since the death of the editor Paolo de Crescenzo in 2013 has closed its doors) under the titles Le Memorie di Jack lo Squartatore, I vampiri di Ciudad Juarez (both translated by Chiara Vatteroni) and I vampiri dell'11 settembre (translated by Stefania Sapuppo). In March 2014 Mosaic Press published The Autobiography of Jack the Ripper as revealed to Clanash Farjeon but this is no longer an approved edition. Beginning in 2017, all four novels will be republished (fully revised) and without the pseudonym by Smart House Books and will be retitled as The Revelation of Jack the Ripper, The Vampires of Juarez, The Demons of 9/11, and The Mask of the Holy Spirit.