John Simm, who Winterbottom worked with on 24 Hour Party People and Wonderland, will play the inmate and Shirley Henderson, who also appeared in Wonderland, will play his wife.
The drama will combine documentary and fiction and will be shot over five years, to enable Winterbottom to explore the changing dynamics of the prisoner's relationships. The shoot will start this year and will be shot mostly within a working prison.
Winterbottom and his team have done extensive research into UK prisons. The director plans to encourage the actors and non-actors to use improvisation techniques during the shoot.
The project is the first to come out of Channel 4's first-look deal with the new TV arm of Revolution, Winterbottom and Andrew Eaton's production company.
Channel 4 Controller of Film and Drama, Tessa Ross added: 'I am delighted that Michael Winterbottom has decided to bring this major project to Channel 4. 7 Days reflects our commitment to produce the most ambitious and innovative films and Winterbottom is one of the UK's innovative and distinctive talents.'