Leigh was born in Paisley, Scotland. She decided she enjoyed acting at a young age and attended PACE Youth theatre. She trained at Bristol Old Vic Theatre School and Mountview Academy of Theatre ArtsLeigh won the BBC Blast Comedy Talent competition at 16 and created her own BBC Radio sketch show with friends called "All The milkmans' Children" with producer Margaret-Anne Docherty .She toured with the Royal Shakespeare Company's "King and Country season " in 2016 and was featured as Alice in Henry V as part of the "Shakespeare Lives" broadcast marking the 400th anniversary of his death.She is now based and working in London.