During the Great Depression of the 1930s, Onwurah’s maternal grandfather was a sheet metal worker in Tyneside shipyards. Her mother grew up in poverty in Garth Heads on Newcastle’s quayside. Her father, from Nigeria, was working as a dentist while he studied at Newcastle University Medical School when they met and married in the 1950s.
After Onwurah was born in Wallsend, Newcastle-upon-Tyne, her family moved to Awka, Nigeria, in 1965 while she was still a baby. Just two years later the Biafra War broke out, bringing famine with it, forcing her mother to bring the children back to Newcastle, while her father stayed there in the Biafran army.
Onwurah graduated from Imperial College London in 1987 with a degree in Electrical Engineering. She worked in hardware and software development, product management, market development and strategy for a variety of mainly private sector companies in a number of different countries – the UK, France, The United States, Nigeria and Denmark while studying for an MBA at Manchester Business School.
Prior to entering Parliament, Onwurah was Head of Telecoms Technology at OFCOM, with a focus on broadband provision.
Before entering Parliament, Onwurah was active in the Anti-Apartheid Movement. She spent many years on its National Executive, and that of its successor organisation, ACTSA: Action for Southern Africa. She also joined the Advisory Board of the Open University Business School.
She was elected to Parliament in 2010 with a majority of 7,466. She described Parliament as a "culture shock" but also said that compared with her engineering background "parliament is the most diverse working environment I've ever been in, the most gender balanced".
Onwurah supported Ed Miliband in the 2010 Labour Party leadership election. Miliband appointed Onwurah as a junior shadow minister for Business, Innovation and Skills on 10 October 2010. In 2013 she was given the role as a Shadow Minister in the Cabinet Office.
In February 2014, Onwurah spoke in a parliamentary debate she had called on gender-specific toy marketing and lent her support to the campaign Let Toys Be Toys. In her speech to the House of Commons, she said:
"Before entering Parliament, I spent two decades as a professional engineer, working across three continents. Regardless of where I was or the size of the company, it was always a predominantly male, or indeed all-male, environment, but it is only when I walk into a toy shop that I feel I am really experiencing gender segregation."
She later told Kira Cochrane of The Guardian, that she believes the limiting of children by gender stereotypes is a serious economic issue, with the proportion of female students on engineering degree courses having fallen from 12% to 8% in the thirty years since she had started studying for one herself. Referring to a shortage of engineers and the UK having "the lowest proportion in Europe of women who are professional engineers" she said "toys are so important and formative, and for me this is about the jobs of the future, about what happens in 10 or 15 years' time. We can't go on with a segregated society."
In the 2015 Labour Party leadership election, Onwurah announced her support for Andy Burnham, having originally nominated Jeremy Corbyn to "broaden the debate". Onwurah is the only engineer in the post-2015 Parliamentary Labour Party.
After Jeremy Corbyn won the leadership election of the Labour party in September 2015, Onwurah was made a Shadow Minister for Business, Innovation and Skills, as well as a Shadow Minister for Culture, Media and Sport.
In the January reshuffle, Onwurah's frontbench role was briefly split between herself and Thangam Debbonaire. According to Onwurah, Corbyn did not mention this change to either woman, or when he reversed his decision, leaving them both in limbo as to their precise responsibilities.
Onwurah noted that the confusion affected two of the ethnic minority, female MPs (out of a 5% total), and argued that employment law required private sector managers to be considerably more sensitive and responsive in handling comparable situations. She stated: "If this had been any of my previous employers in the public and private sectors, Jeremy might well have found himself before an industrial tribunal for constructive dismissal, probably with racial discrimination thrown in".
A spokesman for Corbyn's office, disputing the lack of "negotiation" in January, said "at no point was anyone sacked. We regret that Chi feels she was singled out, but this was clearly not the case. Chi Onwurah’s comments relate to a discussion about the delineation of shadow cabinet roles last January, as is not uncommon in both shadow cabinets and cabinets."
Onwurah later wrote that "I made no accusation of racism against Jeremy", after claims had been made of her "playing the race card".
Onwurah backed Owen Smith in the 2016 Labour leadership election, but remained a Labour frontbencher. In August 2016, during the Labour leadership campaign she publicly supported Owen Smith's calls on a rerun of the referendum on the UK's EU membership
Onwurah retained her seat at the 2017 general election, increasing Labour's share of the vote to 65%. Newcastle Central was the first constituency to declare a result.
Onwurah supports Newcastle United FC.