The Democrat narrowly defeated by Arlen Specter in the 1992 Senate race is still against him despite the party switch.
Lynn Yeakel is scheduled to endorse Sestak Nov. 12 in Philadelphia.
A little-known businesswoman at the time, Yeakel challenged Specter after seeing him question Anita Hill during the Supreme Court Justice Clarence Thomas’ confirmation hearings. Specter won that race by a slim margin of 49 percent to 46 percent.
“I’ve known Joe for four years and he has the character and integrity to represent our party and our Commonwealth in Washington,” Yeakel said.