"I do think the old guard of the party gets a little too crusty and a little too anti-ideas, and I think that's unfortunate," Gingrich told CNN.
Gingrich's comments come on the heels of a speech at the Conservative Political Action Conference (CPAC) on Thursday by Sen. Rand Paul (R-Ky.), who chastised the GOP as "stale and moss-covered."
"I think they should have invited both governors to speak," Gingrich said. "They're both remarkable reformers."
But while Gingrich bemoaned those in his party who held "crusty" ideas, he said he continued to believe that "in the long run, marriage will be between a man and a woman" in light of Sen. Rob Portman's (R-Ohio) revelation that he had a gay son and now supported gay marriage.
Gingrich did say, however, that the country faced "practical legalities which is different than what we think the moral principles are," arguing essentially that the complexity involved in different states holding different standards on gay marriage could necessitate a sweeping redefinition of the institution.
"We're faced with realities that are different than my personal beliefs," Gingrich said. "I believe as the Bible teaches that marriage is between a man and a woman — I actually believe marriage is between a man and a woman no matter what a politician decides, I don't think they have the power to change what is a religiously inspired definition. But it is an objective fact that a number of states have legalized relationships between same-sex couples and that's going to create in American society a great deal of complexity."
Still, Gingrich said he was not going to "second guess" Portman's decision to voice support for same-sex marriages.
"When you have somebody in your immediate family that comes in, you have three choices: You can say, 'I believe in my principles so much, I'm kicking you out.' You can say, 'I still believe in my principles, but I love you.' Or you can say, 'Gee, I love you so much I'm changing my principles.' Rob picked the third path, that's his prerogative," Gingrich said.