Ms Stein made the announcement during a Tuesday night launch with labour organiser Chris Smalls and Palestinian rights advocate Miko Peled.
Her announcement comes weeks after political activist Cornel West left the Green Party to launch his own presidential campaign as an independent candidate.
The environmentalist was the Green Party's presidential nominee in 2012, but it was her candidacy in 2016 that was considered to be the most consequential.
Ms Stein received a little more than 1 per cent of the national vote that year, but it was her performance in several battleground states that potentially played a significant role in the race between Democratic nominee Hillary Clinton and Donald Trump, then the Republican nominee.
Ms Stein's votes in those three states – Wisconsin, Michigan and Pennsylvania – exceeded the vote margin between Mr Trump and Ms Clinton, leading some analysts to believe her presence helped tip the race in Mr Trump's favour.
Her inclusion in the 2024 field adds more complexities for Mr Biden, who faces questions over his age, his handling of the economy, the US southern border and his administration's response to the Israel-Gaza war.
With an approval rating hovering below 40 per cent, the incumbent president could also see voters move to support Mr West's independent bid or the candidacy of anti-vaccine activist Robert F Kennedy Jr.
Meanwhile, Mr Trump holds a commanding lead over his Republican rivals and is the heavy front-runner to secure his party's nomination for president.
Mr Biden currently trails Mr Trump in five of six battleground states a year before election day, according to recent polling conducted by The New York Times and Siena College.