Somerhalder was born in Covington, Louisiana. He has a brother, Bob, a former professional cyclist and a sister, Robin, a broadcast journalist. His father, Robert Somerhalder, was a building contractor of French and English descent, and his mother, Edna, who is of Irish and Choctaw descent, grew up on a pig farm in Mississippi. The surname "Somerhalder" originates from his adoptive great-grandfather. His biological great-grandfather, a wealthy English landowner, got one of his mistresses pregnant and paid an immigrant worker of his to marry this woman and give the baby a name, which was Somerhalder. The biological great-grandfather's name was Hull.

Somerhalder's parents divorced when he was thirteen. He grew up with his mother, whom he has described as being "very spiritual", she raised the young Ian on Eastern medicine and organic foods. "She's very spiritual," says Somerhalder. "She made my baby food and had me on blue-green alga probably since I was in third grade. I never