Born in Staincliffe hospital in Dewsbury, England, Dean's family from his mothers side heritage is of Gaelic descent which retraced all the way back to The Isle Of Man, where Dean still has family. His father's side were known to be of fighters and farmers which traveled the Yorkshire region of Great Britain.

The former professional extreme sports athlete was named by his uncle after the Oscar winning 1950s American actor Dean Jagger and chose for himself the same profession. Dean began acting in school productions at age 14 after a chance meeting with actor Michael Douglas while sailing with his father off the coast of Spain. He joined the theatre appearing in numerous stage productions.