Alison King was born at the Leicester Royal Infirmary. She is the youngest of three daughters and a son born to Alex and June King, who were both Nurses at the hospital. She was raised in the family home first in Ratby Lane, Markfield, Leicestershire where she went to Markfield Mercenfeld Primary School and was taught by Tracey Lee, mother of Sammy Lee, and Gillian Sykes, then in Kirby Muxloe. She attended South Charnwood High School, where she first took an interest in acting. She continued to act while attending Groby Community College, where a Teacher would offer drama and dance classes to students in their free time. Alison was raised as a Christadelphian and attended the Christadelphian Church at Westleigh, Leicester, where she was baptised as a teenager. At the age of 18, King moved to Newquay, Cornwall, where she worked at Fat Willys Surf Shack. She surfed in her spare time, and spent four years as a dental nurse. When she was 22, she enrolled at the North Cheshire Theatre School. While at drama school, she underwent cosmetic surgery at a London dental practice to improve her smile, stating her teeth had been ruined by sucking her thumb as a child, and later had more surgery in 2015. During her time there she got her first television role, playing Helen, a hair salon crimper, in two episodes of Brookside. Before the conclusion of her three-year diploma, she was cast in the major role of Lynda Block in Sky One's Dream Team.