Kit served as a trustee of Prisoners Abroad from 2011 to 2014. She has worked in the criminal justice system for the majority of her working life, in criminal and family law and as a magistrate (Justice of the Peace). She sat on adoption panels, worked as an adviser for Social Services and has written training manuals on adoption and foster care, focusing on mixed parentage, minority ethnic communities, social cohesion and project management. Her debut novel My Name Is Leon was an international bestseller, shortlisted for the Costa First Novel Award, longlisted for the Desmond Elliott Prize and won the Kerry Group Irish Novel of the Year Award for 2017. In 2022 it was adapted for television by the BBC. Her second novel, The Trick to Time, was longlisted for the Women's Prize and her young adult novel Becoming Dinah was shortlisted for the Carnegie CLIP Award 2020. A collection of short stories, Supporting Cast, was published in 2020. An anthology of working-class memoir, Common People, was crowdfunded and edited by Kit in 2019. Kit founded her own TV production company, Portopia Productions and the Big Book Weekend, a free digital literary festival in 2020 and was named the FutureBook Person of the Year 2019. She is an ambassador of Well-being in the Arts and a trustee of The Reading Agency. Kit is a Fellow of the Royal Society of Literature and Professor and Writer in Residence at Leicester University. Her memoir Without Warning and Only Sometimes was published in August 2022.