For his part, Corbett said he expected such a response from some.
The bill's sponsors in the House and Senate applauded Corbett for leadership and called it a major step forward.
"I am glad the governor has joined the great mass of public opinion that has evolved on this civil rights issue," said Rep. Dan Frankel (D., Allegheny), sponsor of the House bill. Pat Browne (R., Lehigh) sponsored the measure in the Senate.
Corbett said he was unaware until this fall that federal law did not protect the rights of gay people in the workplace, housing, and public accommodations.
The bill, now pending in committee, would amend the Human Relations Act to add sexual orientation and gender identity to protected categories.
The law already bans discrimination on the basis of race, color, religion, ancestry, national origin, gender, education status, handicap, or disability.
Corbett said Wednesday that he would sign a nondiscrimination bill if it reaches his desk.
But the fight is far from over.
Rep. Daryl Metcalfe (R., Butler), who as chairman of the state government committee controls movement of the bill, said he had no intention of putting it up for a vote.
"If I brought it up for a vote, it would be defeated," said Metcalfe. "A majority of the Republican caucus is not supportive of the bill."
Browne, however, said he was confident that if the bill came up for a vote on the floor of either chamber, it would pass. He added that Metcalfe should not hold up the process for his personal beliefs.
Although the bills exempt religious institutions and businesses with a religious affiliation, Metcalfe said he believes passage of such a law would "persecute Christians" who do not want to "help facilitate homosexual activities."
Rep. Brian Sims (D., Phila.), the first openly gay elected member of the legislature, held a news conference Wednesday to hail the governor's announcement as evidence that "civil rights clearly is not just a Democratic issue."
The debate over gay rights was reignited as a new poll was released showing Corbett still struggling in the polls, even with the successful passage of his transportation funding bill.
The Quinnipiac poll released Wednesday shows Corbett with a 36 percent positive approval rating, his worst net score ever for that poll. While 56 percent of voters say Corbett does not deserve reelection, 36 percent say he does.
Sims said whether Corbett's move was political does not matter.
"If a governor who fears he might lose reelection feels that he has to come out in support of LBGT civil rights as a way of rescuing a failing campaign, fantastic. I'll take it," said Sims. "Because he's right. He should be supporting this. A majority of Pennsylvanians support this."