Mol was born in Amsterdam, and was one of the first openly gay actors in the Netherlands. He married Lucy Bor in 1948. They couple had a child the following year, actress Kika Mol but divorced in 1955.
On 16 March 1998, Mol registered his relationship with his partner Guerdon Bill. Their relationship lasted until Guerdon's death on 17 August 2003. Mol died in Laren on 9 March 2004 from an aneurysm, aged 87.