Harris was the Member of Parliament (MP) for Glasgow Cathcart from 2001 to 2005, and for Glasgow South constituency from 2005 to 2015. He first entered government when he was made a Parliamentary Under-Secretary of State at the Department for Transport in September 2006 by PM Tony Blair. When Gordon Brown took over as Prime Minister in June 2007, Harris kept his junior ministerial role but, in the October 2008 reshuffle, he was sacked and returned to the backbenches.
Tom Harris was born in Ayrshire and raised in Beith, Scotland. He was educated at the Garnock Academy in Kilbirnie and Napier College, Edinburgh, where he was awarded an HND in Journalism in 1986. He worked as a trainee newspaper journalist with the East Kilbride News in 1986 before joining the Paisley Daily Express in 1988.
He was appointed as a press officer with the Scottish Labour Party in 1990, moving to the same position with Strathclyde Regional Council in 1992. He was briefly the senior media officer with the City of Glasgow Council in 1996 before joining East Ayrshire Council later in the same year as a public relations manager. In 1998, he became the chief of public relations at the Strathclyde Passenger Executive, where he remained until his election to the Parliament of the United Kingdom.
Harris joined the Labour Party in 1984. He was active in the Edinburgh South Constituency Labour Party and was elected as the chairman of the Glasgow Cathcart Constituency Labour Party for two years in 1998. During his time at this post, he tried to stop the closure of the ABC Muirend/Toledo cinema, but was unsuccessful.