Williamson, who averaged 22.6 points and 8.9 rebounds while shooting 68 percent from the field in his one season at Duke, has been the consensus No. 1 choice for months, making the Pelicans' draft decision the easiest since the Cleveland Cavaliers selected LeBron James with the first pick back in 2003.
"I mean, I don't know what to what say," an emotional Williamson told ESPN after his name was called by NBA Commissioner Adam Silver at Barclays Center in Brooklyn. "I didn't think I'd be in this position. My mom sacrificed a lot for me. I wouldn't be here without my mom. She did everything for me."
The 6-foot-7, 285-pound Williamson will have more of a burden placed on him after the Pelicans agreed over the weekend to trade Davis to the Los Angeles Lakers in exchange for point guard Lonzo Ball, forward Brandon Ingram, shooting guard Josh Hart and three first-round draft choices.
When asked if he had a message for his new fanbase in New Orleans, Williamson's response was brief: "Let's dance."
The Memphis Grizzlies, fresh off trading veteran point guard Mike Conley to the Utah Jazz a day earlier, drafted Murray State's Ja Morant as Conley's heir apparent with the No. 2 pick. The New York Knicks drafted forward RJ Barrett, Williamson's Duke teammate, with the third overall pick to huge cheers from the New York crowd.
The Los Angeles Lakers took Virginia forward De'Andre Hunter with the fourth overall pick, but that was in name only. Los Angeles sent the fourth pick to New Orleans as part of the Davis trade before Pelicans General Manager David Griffin flipped it to the Atlanta Hawks earlier Thursday in exchange for the No. 8, No. 17 and No. 35 overall picks, along with a protected first-round pick from Cleveland in 2020 that Atlanta had.
In addition to the No. 4 pick, the Hawks will receive the No. 57 overall pick, a future second-round pick and forward Solomon Hill from New Orleans.
Neither the Davis trade nor the trade with the Hawks can be finalized until July 6 -- coincidentally, Williamson's 19th birthday -- when the moratorium marking the start of the new NBA year comes to an end. As a result, Hunter was outfitted with a Lakers hat and the draft board behind the stage listed the pick as belonging to the Lakers.
The Cleveland Cavaliers rounded out the top five by taking Vanderbilt point guard Darius Garland, who played in just five games this past season because of a knee injury. The Phoenix Suns took Texas Tech guard Jarrett Culver with the sixth overall pick, but reports indicated that Phoenix would trade Culver's rights to the Minnesota Timberwolves in exchange for the No. 11 overall selection and power forward Dario Saric.
North Carolina guard Coby White went to the Chicago Bulls at No. 7, while the Hawks -- likely picking for the Pelicans -- selected Texas center Jaxson Hayes at No. 8. Gonzaga forward Rui Hachimura became the first player born in Japan to be taken in the draft when the Washington Wizards chose him at No. 9. The Hawks, picking for themselves this time, took the third Duke player of the night, guard Cam Reddish, to conclude the top 10. With that selection, Duke joined Florida in 2007 as the only programs with three top-10 picks in the same year (Al Horford, Corey Brewer and Joakim Noah).
It was a big night for the Atlantic Coast Conference, which saw a record six players taken with the first 11 picks after North Carolina's Cameron Johnson went at No. 11 to the Timberwolves -- though his final destination was expected to be Phoenix.
The Associated Press contributed to this report.