The 53-year-old Melvin beat 54-year-old Jack Panella in the general election Tuesday that will change the partisan balance of the seven-justice Pennsylvania Supreme Court.
Both candidates are sitting judges on the Superior Court - Melvin in Pittsburgh and Panella in Bethlehem.
Melvin's victory restores a one-seat majority the GOP lost in 2007.
Melvin refused to accept the judicial pay raise that emerged from the failed 2005 legislative pay raise. She continues to return to the state Treasury the after-tax portion of her salary increases granted since then.