Opperman born in Wiltshire and was educated at Harrow School. Opperman has an honours degree in law from the University of Buckingham and a first class diploma from the University of Lille, France.
Opperman was called to the bar in 1989. He spent 20 years as a barrister of which 15 years were spent predominantly at the criminal bar. Opperman prosecuted and defended in a number of murder and rape trials.
While a barrister, he did many years of pro bono work with the Western Circuit Free Representation Unit and the Bar Pro Bono Unit, providing free legal assistance in hundreds of cases on behalf of Victim Support and Citizens Advice Bureau. The Times named him "Lawyer of the Week" in 2007 and was awarded the Bar Pro Bono Award by the Attorney General, Lord Goldsmith QC, for his voluntary work on behalf of victims in Criminal Injuries Compensation Appeals. In 2009 the Attorney General, Baroness Scotland QC, presented him with a Pro Bono Hero award in the House of Commons for his work on preventing hospital closures. He is now a "door tenant" at 3PB and is no longer in active practice at the Bar having committed to being a full-time Member of Parliament.
Opperman previously stood for election to Parliament in Swindon North at the 1997 general election and for Caernarfon in 2005. He was a Councillor in Kennet from 1995 to 1999.
Opperman became interested in national politics after giving up his time as a barrister for free to lead a campaign to oppose the closure of the NHS's Savernake Hospital at Marlborough, which he credited with saving his mother's life from cancer.
Opperman was elected at the 2010 general election as the Member of Parliament (MP) for Hexham. He was one of the first MPs in the United Kingdom to employ an apprentice.
Opperman runs a series of social action projects in the North East. In 2010 he established a work experience scheme based in his Hexham office to give young people an insight into politics and experience in work. Since its inception almost 100 local young people have taken part in the programme. During Christmas 2011, he collected presents for soldiers serving abroad in Afghanistan. In 2012, he coordinated the collection of more than 300 toys for disadvantaged children in north east England as part of the Northumberland Conservatives' Christmas appeal, "Buy One More Toy".
In September 2012 Opperman was appointed as Private Parliamentary Secretary (PPS) to Mark Harper, the Immigration Minister at the Home Office.
Opperman has previously described himself as "rather on the left" of the Conservative Party and has previously opposed regional pay but supported the Living Wage, regional banks, and industrial activism. He called for his party to do more to show it supports "the hard working people in our public sector". In 2012, the New Statesman magazine summarised his positions on low wages, corporate responsibility, and apprenticeships in an article called "Meet the Tories the left should be frightened of".
According to the website "They Work For You" Opperman spoke in 75 debates in the last year of the 2010–15 parliament — well above average amongst MPs. He has received answers to 43 written questions in the last year — above average amongst MPs and voted in 73.38% of votes in this Parliament with this Party. Opperman's interests in Parliament include fuel poverty, vocational education, the future of the Falklands Islands, assisted dying and prison reform.
On 8 August 2013, Opperman declared his support for the Living Wage in an article for the New Statesman. In this article he asked "How and why did we let it become acceptable for a full-time job not to pay enough to live on?".
In 2014, Opperman caused minor controversy for mistaking a member of the public for Mario Balotelli whilst at a drugs policy debate. Balotelli was, in fact, at the Melwood training ground in Liverpool.
In 2015, Guy Opperman was named by the Independent Parliamentary Standards Authority for not paying £161 in expenses due, this was later revised to £32.
Guy Opperman was appointed as Parliamentary Under-Secretary of State at the Department for Work and Pensions on 14 June 2017 . He quickly found himself mired in controversy in the national press, when footage from 2013 was uncovered showing him stating that he understood what it was like to live on a zero-hours contract because he once worked as a £250-per-hour barrister . Weeks later, in response to the group Women Against State Pension Inequality, he was quoted as saying that older women who face cuts to their state pension could take up apprenticeships as a route to re-employment .
In April 2011, Opperman was diagnosed with a brain tumour after suffering from headaches whilst at work in Parliament. He was rushed to hospital on the advice of his fellow Conservative MP and doctor, Daniel Poulter, and underwent emergency surgery. He recovered fully after several months. Opperman has written about his experience, recording his "incredible debt" to the NHS and is a leading champion of the National Health Service in Parliament.
Guy Opperman has raised almost £10,000 for charity including over £4,000 in 2011 for the National Brain Appeal at the National Hospital for Neurology and Neurosurgery which he credits with saving his life after suffering from a brain tumour. He and Labour MP Paul Blomfield, who also had a brain tumour in 2011, walked the first section of the Pennine Way in 2012 to raise money for Headway UK. In 2012, Opperman walked 280 miles from Sheffield to Scotland raising £2,500 for the Great North Air Ambulance.
Opperman was a director of his family engineering business until 2009. Opperman is a supporter of Middlesbrough Football Club. On 2 June 2017, during his general election campaign, Guy married his partner Flora but was unable to go on a honeymoon due to the campaign.
Opperman is an amateur jockey and rode his first winner in 1985. He continues to ride and has won a number of point-to-point horse races, including at Downhills, Corbridge just after his selection as the Conservative Party Candidate for Hexham in 2009.
In October 2012, Opperman had his first book published, Doing Time, an examination of the prison service and offender rehabilitation in the United Kingdom. In it he offers a consideration of re-offending, prisoner training, drug rehabilitation, prison management and payment by results in the prison system.
Opperman is a member of the Advisory Board of the High Pay Centre and has co-authored an essay with Green Party MP Caroline Lucas and TUC General Secretary Frances O'Grady entitled "Better Business: Moral Matters". In the essay he contrasts community-focused businesses in his own Northumberland constituency with the lack of responsibility demonstrated by the banking sector.
Opperman's blog was awarded a "Top MP's Blog" award by Total Politics magazine in 2010.