Iain Glen was born in Edinburgh, Scotland and trained at RADA where he won the Bancroft Gold Medal. He was married to Susannah Harker from 1993 to 2004; they have one son, Finlay (born 1994). He is now married to Charlotte Emmerson and they have a daughter Mary (born September 2007). In 1990, he won the Silver Bear for Best Actor at the 40th Berlin International Film Festival for his role in Silent Scream.
It was announced on August 20, 2009 that Glen would star as Ser Jorah Mormont in the HBO series Game of Thrones. He appeared in the second series of Downton Abbey as Sir Richard Carlisle, a tabloid editor who is a suitor to and subsequently engaged to Lady Mary.
Iain Glen is the younger brother of Hamish Glen, theatre director, artistic director of The Belgrade Theatre, Coventry, and formerly artistic director of the Dundee Repertory Theatre.