Lightwood was born in 1980 and grew up in South Shields.[6] After his family home was repossessed when he was aged 13, he was forced to live with his grandmother, away from his parents.[7] Lightwood has a degree in theatre acting from Bretton Hall College and bought his first house in Wakefield.[6]
On 3 May 2022, Imran Ahmad Khan resigned as MP for Wakefield after being convicted of sexually assaulting a teenage boy, thus forcing a by-election. After Lightwood has been included on the shortlist for the Labour candidate, entire CLP executive committee (barring one externally appointed individual) walked out of the meeting. At final selection meeting on 15 May, there was a further substantial walkout of members, after which Lightwood was chosen as the official candidate.[11][12][13][14][15] At the by-election held on 23 June 2022, Lightwood was elected as MP with a 4,925 majority.[16]
Lightwood lives in Ossett within the Wakefield constituency with his husband, having pledged to move from his previous home in Calderdale to Wakefield following his election.[18][10]