Kilmer was born December 31, 1959, in Los Angeles, the son of Gladys Swanette (née Ekstadt) and Eugene Dorris Kilmer, an aerospace equipment distributor and real estate developer. His mother was of Swedish descent. His father's ancestry included English, Scots-Irish, French and German. His parents divorced in 1968 when he was 8 years old. Kilmer's grandfather was a gold miner in New Mexico, near the border with Arizona. In 1977 Kilmer's younger brother Wesley drowned in a swimming pool at age 15; their father died in 1993.