After his 1997 electoral defeat, Michael turned to journalism. He wrote about walking as a pilgrim on the Santiago Way, and working as a hospital porter. He had a weekly column in The Scotsman. He had a three part series for Channel 4 about politics Portillo's Progress, and a programme in BBC2's Great Railway Journeys series, which was partly a biography of his late father, and radio programmes on Wagner and the Spanish Civil War.
Michael was re-elected to Parliament in a by-election in Kensington and Chelsea in November 1999 and was Shadow Chancellor of the Exchequer February 2000 - September 2001. Following the Conservatives' election defeat in 2001, Michael unsuccessfully contested the leadership of the party. In 2005 Michael left the House of Commons.
He has made a number of television programmes for BBC2 including Art that shook the world: Richard Wagner's Ring, Portillo in Euroland, Elizabeth I in the series Great Britons, When Michael Portillo became a single mum, and Portillo Goes Wild in Spain (a natural history programme). For BBC4 he has made several series of Dinner with Portillo, a discussion programme. In 2006 he joined The Moral Maze team on BBC Radio 4. In 2003 he began the weekly political discussion programme This Week on BBC1 with fellow presenters Andrew Neil and Diane Abbott MP. Beginning in 2004 Michael became a weekly columnist on The Sunday Times and was the theatre critic of The New Statesman between 2004 and 2006.