Family
- father William O'Donnell Sr:
- mother Julie O'Donnell:
- siblings : O'Donnell is the youngest of seven children, with four sisters and two brothers
- daughter Lily Anne O'Donnell: Born Sept. 3, 1999; mother, Caroline Fentress
- son Christopher Eugene O'Donnell Jr: Born Oct. 24, 2000; mother, Caroline Fentress
- daughter Maeve Frances O'Donnell: Born Dec. 10, 2007; mother, Caroline Fentress
- son Finley O'Donnell: Born March 24, 2006; mother, Caroline Fentress
- son Charles McHugh O'Donnell: Born July 11, 2003; mother, Caroline Fentress
Companions
- Reese Witherspoon: reportedly dated briefly
