William Reibert Mapother, Jr. ( /ˈmeɪpɒθər/; born April 17, 1965) is an American actor and former teacher, perhaps best known for his role as Ethan Rom on the television series Lost. Mapother was born in Louisville, Kentucky, the son of Louisa (Riehm) and William Reibert Mapother, Sr. He is of English, Irish, and German ancestry. He is a first cousin of actor Tom Cruise (whose given name is Thomas Cruise Mapother IV). Mapother has appeared in five movies starring Cruise. He had a cameo role in Minority Report, Vanilla Sky, and supporting roles in Mission: Impossible II, Born on the Fourth of July, and Magnolia. Mapother has two sisters, Katherine and Amy (an occasional actress, born February 17, 1974), both born in Louisville, Kentucky. His father was an attorney, bankruptcy consultant and judge in Louisville, between 1967 and 1970; William Reibert, Sr., died on June 22, 2006, after fighting lung cancer and pulmonary fibrosis. Mapother graduated from the University of Notre Dame as an English major, and then taught high school in East Los Angeles for three years before becoming an actor.