Boreanaz was born on May 16, 1969, in Buffalo, New York, where his father, Dave Roberts (born David Thomas Boreanaz), was working as a weather forecaster and children's show (Rocketship 7) host as Dave Thomas, for ABC affiliate WKBW-TV. His mother, Patti Boreanaz, was a travel agent. He has two older sisters, Bo and Beth. He is of Italian and Slovene descent on his father's side (the surname Boreanaz is of Slovenian origin and was originally spelled "Borjanac" or "Berginc"). His mother is of half Slovak and part Irish, German, French, and Swiss descent.