- Mondale was the 1984 Democratic presidential nominee
- The DNC chair race has largely been viewed through the prism of the 2016 Democratic primary
The move gives the two top contenders to helm the party -- Ellison and former Labor Secretary Tom Perez -- one vice presidential endorsement each, after Joe Biden backed Perez earlier this week.
It comes as Democrats head to Detroit for their third of four "future forums" Saturday, where candidates for party leadership lay out their visions, before the DNC's 447 voting members select their new chair in a late-February meeting in Atlanta.
"Keith was a Minnesota star in the state legislature and now in the US House. Keith believes that we need to help all Americans succeed, and this message of inclusiveness is one that has resonated with people in the 5th Congressional District in Minnesota, who have re-elected Keith five times and who have turned out to vote in increasing numbers ever since Keith took office," Mondale said in a statement. "Keith is exactly the type of person our party needs right now, and I know he'd use his talents to elect Democrats across our country if he's the next DNC Chair."
Mondale, the 1984 Democratic presidential nominee, is a former Minnesota senator and US ambassador to Japan.
Though both Ellison and Perez reject it, the DNC chair race has largely been viewed through the prism of the 2016 Democratic primary -- with Bernie Sanders endorsing Ellison and Perez considered a close ally of Hillary Clinton.
Biden -- stepping back into politics just two weeks after he and President Barack Obama departed -- endorsed Perez on Wednesday.
"Tom knows how to talk to people, not down to them. He knows how to explain why our party's core beliefs matter to the immigrant family in Arizona and the coal miner in West Virginia. That matters," Biden said.
Sanders shot back -- casting Perez as part of the "failed status-quo approach" in a statement. In the DNC race, Sanders said, "the question is simple: Do we stay with a failed status-quo approach or do we go forward with a fundamental restructuring of the Democratic Party?"