[4][5] She was one of four children; her father died when she was a child and her mother, politician Martha Osamor (née Oburotha), had to work "three, sometimes four jobs".

[15][16] On 27 June 2016, after the resignations of numerous members of Labour's ministerial team due to disquiet over the leadership of Jeremy Corbyn, Osamor was appointed Shadow Secretary of State for International Development.

[23][24] On 29 August 2019, she warned that the monarchy could be abolished, following Queen Elizabeth II approving Prime Minister Boris Johnson's plan to suspend Parliament.

[28] Upon being doorstepped by reporter from The Times about the issue, Osamor threw a bucket of water, shouted profanities, and said "I should have come down here with a...bat and smashed your face open".

[29][30][31][32] Osamor was first referred to the Parliamentary Commissioner for Standards in November 2018, by a Conservative MP, and the investigation was expanded following the incident with the journalist.

[33] Osamor resigned from the Shadow Cabinet on 1 December 2018,[34] stating she needed "to concentrate on supporting my family through the difficult time we have been experiencing".

[38] Osamor accepted that she broke the rules and apologised to the Commissioner, although she later commented that she was "the target of a witch-hunt, and that race and class were factors".

[40][41] A ban on MPs employing family members and other ‘Connected Parties’ came in to effect after the 2020 general election, however it was not applied to existing employees.

[42] In October 2019, local party members voted for Osamor to face a re-selection contest to stand at the next general election.

[45][46] In January 2022, Osamor and four other Labour delegates to the Parliamentary Assembly of the Council of Europe tabled ten amendments to a resolution on "Combating rising hate against LGBTI people".

[48][49] On 28 January 2024, Osamor had the Labour Party parliamentary whip withdrawn pending an investigation into comments she made about Holocaust Memorial Day in her weekly newsletter.