GOP opponents were critical of the president's new position, saying it was politically calculated and a pander to his base.
Polis, the first openly homosexual member of Congress who is also a parent, called Obama's announcement "great news" for the institution of marriage and American families.
"The president like so many American families has come to the recognition that gay and lesbian Americans ought to be able to have committed relationships and have public recognition of those relationships and have the same rights and responsibilities in marriage as other Americans," he said.
Public opinion has shifted toward support of same-sex marriage in recent years. A Pew Research Center poll last year found 59 percent of Americans aged 18-30 support legalizing gay marriage.
However, thirty U.S. states now have some form of a legal ban on couples of the same sex wedding.
North Carolina overwhelmingly voted in favor of a state constitutional amendment banning same-sex marriage Tuesday, a referendum the Obama team called "divisive and discriminatory."
Despite his disagreement, Obama told ABC's Robin Roberts that he believes the issue will be handled at the state level.
"Historically, this has not been a federal issue," he said in an interview that aired Thursday on "Good Morning America."
Polis agreed with Obama's views that marriage will be defined by local, not federal government.
"States are where the definition of marriage resides … No one's talking about the federal government defining marriage, it's certainly up to each state how to do that," said Polis.