He was a serious contender for the role of Castiel in "Supernatural" before Misha Collins was cast. He later got to play the recurring role of Lucifer a year later.
In his free time, he actively participates in a variety of sports, including martial arts, kickboxing, professional Thai boxing, Judo, Karate and Ju-Jitsu.
His father was of half Italian and half Russian descent. Mark's maternal grandfather was of Swedish ancestry, and Mark's maternal grandmother had Scottish, Irish, and English roots.
In two of his most famous roles, he has played immortal and extremely powerful characters. In Lost he played Jacob, the almost god-like protector of the mysterious island, and in Supernatural he played Lucifer, a villainous fallen angel.