Obama's sweeping, $500m (¤375m) plan, a month after the school massacre in Connecticut, marks the most comprehensive effort to tighten gun laws in nearly two decades.
But his proposals, most of which are opposed by the National Rifle Association, face a doubtful future in a Congress where Republicans control the House of Representatives.
Seeking to circumvent at least some opposition, Obama yesterday signed 23 executive actions, including orders to make more federal data available for background checks and end a freeze on government research on gun violence.
"To make a real and lasting difference, Congress, too, must act," Obama said, speaking at a White House ceremony with children and their parents.
The president's announcements capped a swift and wide-ranging effort, led by Vice-President Joe Biden, to respond to the deaths of 20 children and six adults at Sandy Hook Elementary School in Newtown, Connecticut.
"This will be difficult," Obama acknowledged. "There will be pundits and politicians and lobbyists warning of a tyrannical assault on liberty."
The president said 900 Americans had lost their lives to gun violence in the four weeks since the school shootings.