"There are thousands of people who have prior Federal convictions for marijuana possession, who may be denied employment, housing, or educational opportunities as a result," he said. "My action will help relieve the collateral consequences arising from these convictions."
The pardon does not cover convictions for possession of other drugs, or for charges relating to producing or possessing marijuana with an intent to distribute. Biden is also not pardoning non-citizens who were in the US without legal status at the time of their arrest.
The Department of Justice is working to devise a process for those covered by Biden's pardon to receive a certificate of pardon, which they can show to potential employers and others as needed.
"The Justice Department will expeditiously administer the President's proclamation, which pardons individuals who engaged in simple possession of marijuana, restoring political, civil, and other rights to those convicted of that offence," the department said in a statement. "In coming days, the Office of the Pardon Attorney will begin implementing a process to provide impacted individuals with certificates of pardon."
Biden is also directing the secretary of Health and Human Services and the US attorney general to review how marijuana is scheduled under federal law. Rescheduling the drug would reduce or potentially eliminate criminal penalties for possession. Marijuana is currently classified as a Schedule I drug, alongside heroin and LSD, but ahead of fentanyl and methamphetamine. The White House did not set a timeline for the review.
But Biden said he believes that as the federal government and many states ease marijuana laws, they should maintain limitations on trafficking, marketing and underage sales.
The move by Biden puts the federal government on course with other big cities like New York that have been moving toward decriminalising low-level marijuana arrests for years. But there's a big divide in the nation as some police departments still believe the drug leads to more serious crime and ignoring low-level offences emboldens criminals.
Advocacy groups praised Biden's announcement, with Kassandra Frederique, the executive director of the Drug Policy Alliance, saying the organisation was "thrilled".
"This is incredibly long overdue," said Frederique. "There is no reason that people should be saddled with a criminal record - preventing them from obtaining employment, housing, and countless other opportunities - for something that is already legal in 19 states and DC and decriminalised in 31 states."
Reverend Al Sharpton, the president of the National Action Network, said Biden's "righteous action today will give countless Americans their lives back". But he added: "The United States will never justly legalise marijuana until it reckons with the outdated policies that equated thousands of young black men with hardened drug pushers."
The move also fulfils one of the top priorities of the Democratic nominee in one of their party's most critical Senate races, as Pennsylvania Lt Governor John Fetterman has repeatedly pressed Biden to take the step, including last month when they met in Pittsburgh.
Fetterman, in a statement, took credit for elevating the issue on Biden's agenda and praised the decision, calling it "a massive step towards justice".
"This action from President Biden is exactly what this work should be about: improving people's lives. I commend the president for taking this significant, necessary, and just step to right a wrong and better the lives of millions of Americans," he said.
