Clive Antony Lewis was born in London on 11 September 1971. He grew up on a council estate in Northampton, the son of a single father. He was the first member of his family to attend university, studying economics at the University of Bradford before being elected student union president, and later vice-president of the National Union of Students (NUS). In November 1995, he was a signatory to a letter that argued for the abolition of student loans.
Lewis was suspended from the role of vice-president of the NUS in 1996 by the president of the NUS, Jim Murphy, for publicly supporting concerns about tuition fees. Murphy's actions were condemned by Ken Livingstone, then a Labour MP. Lewis ran for president of the National Union of Students in 1996 on a platform of full grants and free education. He lost the election to Douglas Trainer.
After completing a post-graduate diploma in journalism, he worked on local newspapers in Northampton and Milton Keynes before being accepted into the BBC's News Trainee Scheme. He went on to work as a broadcast journalist in Nottingham, Norwich, and Coventry. He then became a senior broadcast journalist and the main reporter on the BBC's Politics Show East.
Lewis joined the Territorial Army, passing out of Sandhurst Military Academy in 2006 as an infantry officer with 7 Rifles. In 2009, he served a three-month tour of duty in Afghanistan. Shortly after returning from his tour of duty, he faced depression, saying "I just felt like I was being crushed by it all." However, he recovered after receiving counselling from the Ministry of Defence.
Lewis was selected as the Labour Party's prospective parliamentary candidate for Norwich South at the party's hustings in November 2011, beating other candidates including the musician Dave Rowntree. Norwich South had been won by Simon Wright of the Liberal Democrats in the 2010 general election by a margin of just over 300 votes, defeating former Home Secretary and Education Secretary Charles Clarke.
In April 2015, Lewis commented in an interview for the New Statesman (in jest), in response to a question on whether he was taking his upcoming victory for granted, he would only lose if he was "caught with [his] pants down behind a goat with Ed Miliband at the other end". He subsequently apologised for the remark, saying he was "sincerely sorry" if anyone had been offended by the comment.
As a candidate, Lewis opposed the Labour Party's position on immigration. Locally, Lewis supported the campaign to prevent Hewett School, a comprehensive school in Norwich, from being turned into an academy.
On 7 May 2015, Lewis was elected MP for Norwich South with a 15.8% majority of 7,654. Lewis, in his victory speech, declared New Labour to be "dead and buried" and promised to stand up for Norwich's most vulnerable against an "onslaught of cuts" by the governing Conservative Party.
In June 2015, Lewis was elected Chair of the All Party Parliamentary Humanist Group. In the same month, he became a patron of the Anti Academies Alliance.
Lewis was one of 36 Labour MPs to nominate Jeremy Corbyn as a candidate in the 2015 Labour leadership election. Corbyn credited Lewis with getting his nominations "off the ground". Lewis has been described as an ally of Corbyn, who was elected leader. In September 2015, he was appointed to the Labour frontbench as a shadow minister in the Energy and Climate Change team.
Following resignations from Corbyn's shadow cabinet after the 2016 EU referendum, Lewis was appointed as shadow defence secretary. In September 2016, at the Labour Party's 2016 Conference, when Lewis was preparing to give his first speech as shadow defence secretary, a section of his speech announcing that he "would not seek to change" Labour's current policy on nuclear weapons was changed by Corbyn's communications advisor Seumas Milne. Lewis was informed of the change by a post-it note. A month later, Corbyn removed Lewis from the defence brief, replacing him with Nia Griffith. Lewis was then appointed as shadow business secretary. The move was viewed as a tactical demotion.
On 8 February 2017, Lewis resigned from the shadow cabinet, citing the Labour Party's decision to whip its MPs to vote to trigger Article 50 to start Brexit negotiations.
In April 2017, Lewis was one of 13 MPs to vote against triggering the 2017 general election. He was subsequently re-elected with a majority of 30.4 per cent.
Clive Lewis was accused of groping a woman at Momentum's "World Transformed" event at the 2017 Labour party conference. In response, Lewis said he was "pretty taken aback" by the accusation and "completely" and "categorically" denied it. On 12 December 2017, he was cleared by Labour's National Executive Committee sexual harassment panel.
Video footage, taken at a fringe event at the same conference, emerged in which Lewis told the (male) actor Sam Swann to “get on your knees, bitch”. Lewis' language attracted criticism from Labour colleague, Stella Creasy, who said: “It’s not OK. Even if it’s meant as a joke, it reinforces menace that men have the physical power to force compliance.” Commenting later, Swann said, "It is clearly jovial and nothing vicious ... I think Clive Lewis is an absolute legend." Lewis subsequently tweeted an apology, in which he described his behaviour as "offensive and unacceptable".
In January 2018, Lewis was reappointed to Labour's shadow frontbench as a shadow Treasury minister, responsible for sustainable economics.
In the 2019 general election, Lewis was returned on a reduced majority of 24.7%. In December 2019, he announced that he would run in the 2020 Labour Party leadership election.