Anne-Marie was born in Somerset on 7 April 1991 as Anne-Marie Nicholson. Her father was born in Ireland, while her mother is from Essex. She appeared in two West End productions as a childLes Misrables when she was six, and Whistle Down the Wind alongside a young Jessie J when she was 12. In addition, Nicholson has practised shotokan since she was nine, won Double Gold in the Funakoshi Shotokan Karate Association World Championships 2002, Gold and Silver in the Funakoshi Shotokan Karate Association World Championships 2007 and Gold in the United Kingdom Traditional Karate Federation National Championships and credits this with teaching her "discipline and focus basically everything I need for this career" but does not have time to practise it frequently, owing to touring restraints.
Anne-Marie cut a solo demo for Rocket Records in 2013 called "Summer Girl". Her solo career was curtailed in order for her to develop herself as an artist; in the interim, she guested on tracks by Magnetic Man, Gorgon City and Raized by Wolves, after which she caught the attention of Rudimental; one of their vocalists left, and so they asked Anne-Marie to replace her. She featured on four tracks on their album We the Generation, of which two were co-features with Dizzee Rascal and Will Heard; the latter, "Rumour Mill", reached number 67 on the UK Singles Chart. She spent two years touring alongside them. Her debut EP, Karate, went out on their then-new label Major Tom's; two singles were released from it, "Karate" and "Gemini", which led to Nicholson gigging as a solo artist.
In early 2016, she released "Do It Right", which peaked at number 90 on the UK Singles Chart, and stated that a full-length album would be released later that year, which at the time had the working title of Breathing Fire. Later in 2016, her single "Alarm" spent one week at number 76 in June before resurfacing a month later; as of 29 July 2016, it has peaked at number 16. In October 2016, Anne-Marie was confirmed to play at the thirty-first edition of Eurosonic Noorderslag in Groningen, Netherlands.
In October 2016, Clean Bandit released their song "Rockabye", which features Anne-Marie and Sean Paul. It spent nine consecutive weeks at number one, and gained the coveted Christmas number one.
In 2017, she released "Ciao Adios", that she previously performed live in preview at KOKO, on 28th November 2016.