Biden acknowledged gun control has traditionally been viewed as the third rail of American politics, recalling that when President Barack Obama asked him to take the lead, the president told him he didn't have to do it if he didn't want to.
"America has changed on this issue," Biden said at the conference at Western Connecticut State University, which the gunman once attended. "There is a moral price to be paid for inaction.
Noting the courage of the families of the victims at Sandy Hook Elementary in nearby Newtown, Biden said elected officials should show political courage.
"We have to speak for those 20 beautiful children who died 69 days ago, 12 miles from here," Biden said. "We have to speak for the voice of those six adults who died trying to save the children in their care that day who can't speak for themselves. You have to speak for the 1,900 people who have died at the other end of a gun just since Sandy Hook in this country."
Biden advocated a series of proposals, including universal background checks for gun owners, a ban on many military-style weapons and a limit on the size of magazines.
"Fewer children will die," Biden said.
U.S. Sen. Richard Blumenthal, who organized the conference with two other members of the state's congressional delegation, said those measures are achievable. He said the Newtown shooting dramatically changed the prospects for gun control.
"Newtown has transformed America, and we need to build on that sense of urgency going forward," Blumenthal said. "Preventing gun violence was thought to be untouchable politically two months ago. That unspeakable horror has given us unstoppable momentum."
Connecticut Gov. Dannel P. Malloy, attending the conference, announced that he wants to immediately ban high-capacity ammunition magazines, require background checks for the transfer of firearms and expand the state's assault weapons ban. He has expressed frustration that the state legislature has not acted more quickly to form a response to the Newtown tragedy.
The gunman, 20-year-old Adam Lanza, killed his mother at their Newtown home before going to Sandy Hook and slaughtering 20 children and six adults. He committed suicide as police arrived.
Other speakers at the conference, designed to give momentum to Obama's gun control proposals, urged Congress to honor the memories of the victims with strong action, including Chris and Lynn McDonnell, whose 7-year-old daughter Grace was among the 26 people killed.
"We ask our representatives to look into their hearts and remember the 26 beautiful lives we lost and pass meaningful laws to help prevent this from happening again," Lynn McDonnell said, leading to a standing ovation.
Malloy, Newtown First Selectman Pat Llodra, state police Capt. Dale Hourigan and the mayors of Bridgeport and Hartford participated, along with other experts in the fields of mental health, law enforcement and education.
Gun makers and lobbyists weren't invited to participate in the conference, but Blumenthal said gun rights advocates will have opportunities in hearings and other forums to express their points of view.