She is known for portraying the role of Zoe Slater on the BBC soap opera EastEnders. In 2007, she starred in the short lived revival of the American television series Bionic Woman. She has appeared as the evil sorceress Nimueh in the 2008 BBC TV series Merlin, and as Lady Christina de Souza in the Doctor Who episode "Planet of the Dead".
Michelle Ryan was born in Enfield, Greater London, and was a student at Chace Community School. A member of a local theatre group since she was 10, she was picked for her role in EastEnders when she was 15 and first appeared on the show in September 2000; for the part, she affected an East End cockney accent, rather than speaking her usual Received Pronunciation.She left the series in late 2005 and has since stated that she has no intention of returning to EastEnders.During summer 2005, Ryan appeared in a run of Who's the Daddy? at the King's Head Theatre. The play by Toby Young and Lloyd Evans is based on the David Blunkett paternity case.
Ryan had a small role in an episode of Marple which screened in February 2006, and also appeared in a small independent film the same year, Cashback.
In May 2007, Ryan revealed she had auditioned the previous year for the role of Vesper Lynd in Casino Royale, eventually given to Eva Green. In late 2007 she appeared in Flick, a Welsh independent film co-starring Faye Dunaway and Leslie Phillips.
Prior to Bionic Woman, she appeared in Jekyll for the BBC, a modern day version of Strange Case of Dr Jekyll and Mr Hyde starring James Nesbitt. It began its six-episode run on 16 June 2007 and was released on DVD in the United States on 18 September 2007, one week prior to her debut in Bionic Woman.
Ryan is signed to Independent Models in London, and is also a patron of children's cancer charity CLIC Sargent.
Michelle Ryan also filmed an ITV romantic drama, Mister Eleven in 2008. It also stars Sean Maguire, Adam Garcia, Lynda Bellingham, Olivia Coleman and Denis Lawson.