Former South Bend, Ind., Mayor Pete Buttigieg will speak at the Democratic National Convention on Thursday in support of his former presidential primary rival, Joe Biden.

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Buttigieg is expected to speak between 9 and 11 p.m. ET on Thursday, shortly before newly minted Democratic nominee Biden takes the (virtual) stage.

In this Feb. 24, 2020 file photo, Democratic presidential candidate former South Bend, Ind., Mayor Pete Buttigieg speaks during a campaign event in North Charleston, S.C. (AP Photo/Matt Rourke)

Thursday is the fourth and final day of the convention. Milwaukee had been preparing to host the convention that was expected to draw tens of thousands of people, but the coronavirus pandemic turned it into an online event.

Here are five things to know about Buttigieg:

1. He went after Biden before eventually endorsing him

While he was still in the 2020 race, Buttigieg did not hold back in criticizing Biden.

“I hear Vice President Biden say that this is no time to take a risk on someone new,” Buttigieg said in January, according to Time. “But history has shown us that the biggest risk we could take with a very important election coming up is to look to the same Washington playbook and recycle the same arguments.”

Buttigieg, second from right, stands on stage before a Democratic presidential primary debate Feb. 19, 2020, in Las Vegas. (AP Photo/John Locher)

2. He was the youngest candidate in the 2020 Democratic field

At 38, Buttigieg is just over the minimum age the Constitution allows for a person to hold the office of president, 35.

His birthday is in January, making him just a few months younger than his former rival Rep. Tulsi Gabbard, D-Hawaii, who turned 39 in April.

3. He's a military veteran 

Buttigieg served as an intelligence officer in the U.S. Naval Reserve and was deployed to Afghanistan in 2014, taking a leave of absence from his role as South Bend's mayor. He's touted his veteran status as among his foreign policy credentials.

Buttigieg shakes hands with supporters at a town hall in Columbia, S.C. on the eve of the South Carolina primary, on Feb. 22, 2020.

Buttigieg picked up a big endorsement from the progressive veterans' group VoteVets.org last year.

4. He used to work for one of the world's largest consulting firms

Buttigieg is a former employee of McKinsey & Co., one of the largest and most prestigious consulting firms in the world. That association has earned him some flak from fellow Democratic candidates, who portrayed Buttigieg as a creature of big business.

That criticism has even come from The New York Times editorial board, which dual-endorsed his competitors Sens. Elizabeth Warren, D-Mass., and Amy Klobuchar, D-Minn.

McKinsey is also famously secretive with its clients, which earned the former mayor even more criticism. The firm eventually made an accommodation for Buttigieg to allow him to name the clients he worked with while at McKinsey between 2007 and 2010.

5. He guest-hosted "Jimmy Kimmel Live" after exiting the presidential race

Buttigieg got a small consolation prize after dropping out of the 2020 race in March: late-night TV host Jimmy Kimmel invited him to guest host his show.

“Running for president was an amazing experience,” Buttigieg said. “The support that our campaign got was unbelievable, and I really thought we had a shot. But it turns out I was about 40 years too young and 38 years too gay.”

Fox News' Tyler Olson and Andrew O'Reilly contributed to this report.