Lennie was born on October 11, 1965 in the United Kingdom, to Afro-Trinidadian parents originated from Nigeria. He attended the Guildhall School of Music and Drama, graduating in 1988. He has appeared in over twenty films, including the 1998 film adaptation of Les Misérables, the Guy Ritchie crime caper Snatch (2000), 24 Hour Party People (2002), and Sahara (2005) and wrote the play The Sons of Charlie Paora, which was performed at London's Royal Court Theatre. He appeared in the short-lived Channel 4 prison drama Buried.
He portrayed Luke Gardner in the BBC terrorism drama The State Within, Bishop David Newman on the BBC spy drama Spooks, and also portrayed Robert Hawkins in the CBS post-apocalyptic television drama series Jericho. He played the role of Cedric Munroe in the 2007 film Outlaw.
He was in a 2008 Channel 4 television drama, Fallout, playing the role of a detective alongside another detective solving a teen-related murder. He also appeared in an episode of Lie to Me. In the AMC Television/ITV miniseries The Prisoner, aired in November 2009, James was "Number 147". He has also appeared in season 2 of HBO's comedy series, Hung, as a fellow pimp who gives Tanya advice. In 2010 he starred as Morgan Jones, a father protecting his son from the zombie apocalypse, in the AMC series The Walking Dead. James was recently in episodes of Human Target as the assassin "Baptiste". He appears in a starring role in the 2010 feature film Tic. He also appeared in the 2011 action film Colombiana and the 2012 sci-fi film Lockout. In 2015 he stars in a medical drama known as Critical where he plays the character "Glen Boyle".
James is the main cook for his family, and has professed a fondness for Caribbean cuisine. His favourite football team is Tottenham Hotspur. He lived in South London and went to school at Ernest Bevin College. He has three daughters – Romy and twins Celine and Georgia - with his longtime partner Giselle Glasman.
- 24 Hour Party People
- The Miracle Maker
- Blade Runner 2049