맥켈런은 영국 잉글랜드 랭커셔의 번리에서 태어났다. 맥켈런은 볼튼 스쿨을 다니면서 볼튼 리틀 씨어터에서 그의 경력을 쌓아갔다. <Peter Pan>, <Cinderella>, <Hamlet> 등에 출연하였다. 그가 셰익스피어 연극의 첫 작품은 <Twelfth Night>에 출연하면서 연기자의 길에 입문하게 되었다. <Macbeth>와 <Midsummer Night’s Dream> 등에 출연하였다. 그는 캠브리지 대학에서 영문학을 전공하였으며, 연극 무대에서의 명성을 날리기 시작하였다.

셰익스피어 전문배우로 불리는 그는 영국 로얄 국립극장 출신의 격조있는 연기로 그가 출연하는 작품의 가치를 증명하는 배우로 인정받고 있다. 그는 엘리자베스 여왕으로부터 기사 작위를 받았다.

Awards
1981 Tony Award for Best Actor ? Amadeus(Play)
1982 Royal Television Society Award for Best Performance ? Walter(Film)
1993 CableACE Award for Supporting Actor in a Movie or Miniseries - And the Band Played On(Film)
1984 Olivier Award for Best Actor in a Revival - Wild Honey(Play)
1984 Evening Standard Award for Best Actor - Coriolanus(Play)
1989 LEvening Standard Award for Best Actor - Othello(Play)
1990 Olivier Award for Best Actor - Richard III(Play)
1995 European Film Award for Best Actor, Evening Standard British Film Award for Best Film - Restoration Will Gates(Film)
1996 Golden Globe Award for Best Actor - Rasputin: Dark Servant of Destiny Nicholas II (Film)
1998 Back Stage West Garland Awards - A Knight Out in Los Angeles(Show)
1998 Saturn Award for Best Supporting Actor, Broadcast Film Critics Association Award for Best Actor, Florida Film Critics Circle Award for Best Actor - Apt Pupil(Film)
1998 British Independent Film Award for Best Actor, Broadcast Film Critics Association Award for Best Actor, Chicago Film Critics Association Award for Best Actor, Chlotrudis Award for Best Actor, Florida Film Critics Circle Award for Best Actor, Independent Spirit Award for Best Lead Male, Kansas City Film Critics Circle Award for Best Actor, Los Angeles Film Critics Association Award for Best Actor, National Board of Review Award for Best Actor, Online Film Critics Society Award for Best Actor, San Diego Film Critics Society Award for Best Actor, San Sebastian International Film Festival Award for Best Actor, Toronto Film Critics Association Award for Best Actor - Gods and Monsters(Film)
2001 Phoenix Film Critics Society Award for Best Cast, Saturn Award for Best Supporting Actor, Screen Actors Guild Award for Outstanding Performance by a Male Actor in a Supporting Role - The Lord of the Rings: The Fellowship of the Ring(Film)
2002 Online Film Critics Society Award for Best Cast, Phoenix Film Critics Society Award for Best Cast - The Lord of the Rings: The Two Towers(Film)
2003 Broadcast Film Critics Association Award for Best Cast, National Board of Review Award for Best Cast, Screen Actors Guild Award for Outstanding Performance by a Cast in a Motion Picture - The Lord of the Rings: The Return of the King(Film)
2004 Pride International Film Festival's Lifetime Achievement & Distinction Award
2006 Annie Award for Best Voice Acting - Flushed Away(Animation)
2009 San Sebastian International Film Festival Donostia Award