The bill, known as the American Rescue Plan Act, passed by a vote of 220 to 211. One Democrat — Representative Jared Golden of Maine — joined all Republicans in voting against the measure. Golden had previously voted against the House version of the bill which passed last week. The legislation will soon head to Mr. Biden's desk, where he will sign it on Friday, the White House said. The Senate approved the bill along party lines following a marathon voting session on Saturday.

Just 49 days into his presidency, Mr. Biden has secured what could prove to be the defining domestic policy accomplishment of his presidency, injecting hundreds of billions of dollars into the economy and bolstering his administration's efforts to accelerate vaccinations, reopen schools and get jobless Americans back to work. The president, Vice President Kamala Harris and first lady Dr. Jill Biden plan to travel to promote the package once it clears Congress and is signed into law Friday, White House press secretary Jen Psaki said.

That's because the relief bill includes an overhaul of the Child Tax Credit (CTC), a 24-year-old part of the nation's tax law that today primarily benefits middle- and upper-income families. The American Rescue Plan overhauls the CTC by expanding the benefit from $2,000 annually to as much as $3,600 per child. It also includes more low-income households and doles out the credit's benefit through monthly cash payments.

Those changes could have a major impact on millions of families, especially low-income households and those whose earnings can fluctuate from month to month. More than 4 million children could be lifted out of poverty, particularly children from Black or Latino families, according to analysis from the Center on Budget and Policy Priorities.