| First Name | William |
| Last Name | Mapother |
| Full Name at Birth | William Reibert Mapother, Jr. |
| Age | 46 |
| Date of Birth | April 17, 1965 |
| Birthplace | Louisville, Kentucky |
| Height | 6' 1" (185 cm) |
| Build | Slim |
| Hair Color | Brown - Light |
| Star Sign | Aries |
| Ethnicity | White |
| Nationality | American |
| University | University of Notre Dame |
| Occupation | Actor |
| Occupation Category | Actor |
| Claim to Fame | Lost |
William Reibert Mapother, Jr. (born April 17, 1965) is an American actor and former teacher, known for his role as Ethan Rom on the television series Lost.
Selected William Mapother film and TV show credits: