WASHINGTON—President Joe Biden on Monday signed into law his $1.2 trillion bipartisan infrastructure bill during a ceremony at the White House packed with some 800 supporters, heralding what he said was a “truly consequential” spending bill that will improve Americans’ day-to-day lives.

But Democrats also emphasized that there is more to come—a $1.85 trillion social spending measure that still faces a close final vote in the U.S. House and  major changes in the evenly divided Senate, where passage will have to come without GOP support.

Biden said the infrastructure legislation— backed by nearly all congressional Democrats, as well as 19 Senate Republicans and 13 House Republicans — is a signal that polarized public officials in Washington can come together to create jobs and solve long-lingering problems.