The biological father of Sabrina Spellman is Edward Spellman.
Edward Spellman was a mortal human who married Sabrina's mother, Diana Spellman, a witch. They had two daughters, Sabrina and her older sister, Hilda.
Edward Spellman died when Sabrina was young, leaving Diana to raise their daughters on her own. Sabrina's half-brother, Ambrose Spellman, is Diana's nephew and was raised by her after his parents died.
Although Edward Spellman was a mortal, Sabrina and her sisters inherited magical abilities from their mother. Sabrina's magical heritage is a central theme in the series.