Hewitt is from curling family. His mother, Canadian-born Lynn Hewitt, played curling in Canada from her childhood. When she met Australian farmer Stephen (Steve) Hewitt, married him and they moved to Australia, her husband began play curling too; several times he was member of Australian national men's team and played on Pacific Curling Championships. Together they moved their son to the sport of curling when he was 6 years old. Lynn and Dean together played as Australian national mixed doubles curling team (team with age difference more than 30 years) at the 2017 World Mixed Doubles Curling Championship and the 2018 World Mixed Doubles Curling Championship