The online fundraiser is Obama's first fundraiser for the presumptive Democratic nominee.
The small-dollar fundraiser raised more than $4 million from more than 120,000 people who paid to attend, The New York Times first reported.
Last month, Biden and the Democratic National Committee surpassed President Donald Trump and the Republican Party in fundraising for the first time, nearly $81 million compared with $74 million.
Obama endorsed Biden in April in a video message posted to Biden's YouTube channel.
Ben Tulchin, who polled for rival Democratic candidate for Sen. Bernie Sanders, I-Vt., who has since dropped out of the race, said that Obama's support is important, especially in the current climate.
Black Lives Matter protests have erupted worldwide since George Floyd, a 46-year-old unarmed black man, was killed by police in Minneapolis, Minn., on Memorial Day, after two other unarmed black people were killed earlier in the year -- Breonna Taylor, 26, who was shot by police in her home in Louisville, Ky., and Ahmaud Arbery, 25, who was killed while jogging in Brunswick, Ga. Protesters have demanded justice and an end to police brutality, systemic racism, and disproportionate killing of black people by police.
"Biden doesn't have the strongest record on criminal justice reform so having Obama there is helpful in reinforcing that issue," Tulchin said. "Given what's going on with criminal justice reform and Black Lives Matter, having the first African American president out there publicly backing Biden is extremely helpful."
Biden has said he would reinvigorate Obama-era police reforms rolled back under th Trump administration.
Among those reforms, under Obama, the Justice Department used pattern-or-practice investigations and consent decrees to address "systemic police misconduct," and "restore trust between police and communities." The Trump Administration's Justice Department limited this action by requiring a political appointee to sign off on these consent decrees. The Obama administration also had policy to reduce private prisons, which the Trump administration rescinded. Biden said he would "stop corporations from profiteering off of incarceration." And Biden said he would also expand funding for transitional housing for formerly incarcerated individuals, which was sharply cut under the Trump administration.
Earlier this month, Biden also pledged to establish in his first 100 days if elected president, a ban on police using chokeholds, creation of a national police oversight commission, and "measures to stop transferring weapons of war to police forces."