"I'm pleased. I think it was fairly clear that when he said he would not defend in court the Defense of Marriage Act that that's where he was moving," Frank told CBS News. "In fact, from the standpoint of federal policy, that was the big decision."
"There is no federal policy on marriage. What you have is the Defense of Marriage Act ... so when the president repudiated it, he really took a major step forward, and I'm pleased that he took the final step," Frank said.
Frank, who plans to retire from Congress this year after 16 terms, told CBS that there is a practical aspect to the president's stance on the issue as well.
"We're going to have some referendums this year, and the president is obviously a particularly influential figure in the African-American community.
The Massachusetts congressman specifically noted Maryland and California as states where Obama's position on gay marriage could have influence.
During his interview with ABC News, Obama also said he believes marriage policy should be defined by state governments.
In January, Frank announced plans to marry his longtime partner this summer, which will make him the first member of Congress in a same-sex marriage.
Massachusetts is one of six states, plus the District of Columbia, that legally recognize marriages between couples of the same sex.