A New York native, Mark returned to New York upon his admittance to the state's bar in 1981 after graduating from the University of Florida (B.A., summa cum laude, 1977) and the American University Law School (J.D., 1980). Following law school, Mark served as an Assistant District Attorney in Bronx County (1980-1985), where he was a Senior Trial Attorney in the Sex Crimes Bureau (1984-1985). During his time as an Assistant District Attorney, Mark met his wife Susan who worked as an Attorney with juvenile offenders and in the Domestic Violence Bureau. Together they have raised three boys. In 1986, he opened his own law practice focusing on matrimonial and family law. Mark was named as a Superlawyer in 2014, 2015, 2016, 2017, 2018, 2019 and 2020.