Obama called for "concrete" proposals within a month from a new task force that will be led by Vice President Joe Biden that will examine new gun control laws, better mental health access and the impact of violent culture.
"I will be putting forward very specific proposals. I will be talking about them in my State of the Union, and we will be working with interested members of Congress to try to get something done," Obama said.
The president said the killings of 20 children aged six and seven and six adults in an elementary school last week should give lawmakers a potent incentive for action, even when initial shock fades.
"The fact that this problem is complex can no longer be an excuse for doing nothing. The fact that we can't prevent every act of violence doesn't mean we can't steadily reduce the violence, and prevent the very worst violence."
Obama said he welcomed public support for measures like the banning of assault weapons, like the one used by gunman Adam Lanza in Connecticut last Friday, and also on outlawing the sale of high-capacity ammunition clips.
He said a majority of Americans also supported background checks for all gun purchases and signaled an effort to expand mental health care, in an effort to deter psychologically troubled people from turning to mass violence.
"We're going to need to make access to mental health at least as easy as access to a gun. We're going to need to look more closely at a culture that, all too often, glorifies guns and violence," he said.
Obama spoke with Americans still traumatized by Lanza's horrific gun rampage, and as more of the victims were laid to rest in the grief stricken picture postcard town in Connecticut.
Biden has a history of framing crime legislation from his years in the Senate, has an affinity with law enforcement services and also enjoys the kind of cordial links with many top Republicans in Congress that Obama lacks.
He will begin his work on Thursday, meeting senior law enforcement leaders from across the United States and key cabinet members at the White House.
Obama's timeline means he will make new legislation to stem gun violence one of the first major issues of his second term, after he is sworn in on January 20.
The president, who comforted relatives of Newtown victims on Sunday, bristled when asked by a reporter whether he had been absent on gun control issues, following mass killings in Colorado, Arizona and Texas on his watch.
"I've been president of the United States, dealing with the worst economic crisis since the Great Depression, an auto industry on the verge of collapse, two wars. I don't think I've been on vacation."
Obama, who many conservatives believe wants to take away their guns, made clear he supported the Second Amendment to the Constitution, which enshrines the right to bear arms in the United States.
But he added: "there is a big chunk of space between what, you know, the Second Amendment means and having no rules at all."
Obama also called on the National Rifle Association, the most powerful gun lobby group which piles pressure on lawmakers over gun rights, to consider its priorities, before senior figures hold a news conference on Friday.
"The NRA is an organization that has members who are mothers and fathers, and I would expect that they've been impacted by this as well, and hopefully they'll do some self-reflection," he said.
The aftermath of the horrific shootings in Connecticut has prompted some pro-gun figures on Capitol Hill to admit that more needs to be done to regulate the sale and use of firearms.
But most evidence of shifting positions has been among Democrats, and there are signs that Republicans, especially those from rural, southern and conservative states may balk at new legislative action.
Democratic Representative Catherine McCarthy, whose husband was gunned down on a New York train in December 1993, however said the uproar after this massacre was different.
"We are fed up with the lack of courage here in Washington to take a stand, to do something," she said.
"We can protect the Second Amendment rights, but we can also protect our communities."
In another development Wednesday, Democratic Senator Jay Rockefeller announced a bill that would require a National Academy of Sciences assessment of links between violent games and violence.
Lanza was reportedly a fan of violent videogames.