Williams beat out teammate Montrezl Harrell and Indiana Pacers big man Domantas Sabonis for the award.
Monday's honor further solidifies Williams' status as the best sixth man in the league. At every one of the six stops in his NBA career, the 32-year-old has consistently provided high-volume scoring off the bench.
Some might have questioned whether Williams would continue to be the player who averaged a personal-best 22.6 points in 2017-18. While his scoring average dropped slightly, he's so far outperforming the three-year, $24 million extension he signed with Los Angeles in February 2018.
Williams appeared in 75 games, averaging 20.0 points and a career-high 5.4 assists while shooting 42.5 percent from the field. He also shot a respectable 36.1 percent from beyond the arc.
According to NBA.com, the Clippers had a 4.4 net rating when Williams was on the floor. That number was minus-2.6 when he was on the bench.
Entering the season, it looked like Los Angeles would struggle to reach the playoffs in the hyper-competitive Western Conference. Bleacher Report's Grant Hughes ranked the Clippers 15th in his preseason power rankings, which put them 10th in the West.
The team had traded Blake Griffin in January 2018 and watched DeAndre Jordan leave ahead of the 2018-19 season. The Clippers were largely bereft of a true star, and they proceeded to deal their best player, Tobias Harris, to the Philadelphia 76ers ahead of the Feb. 7 trade deadline. Danilo Gallinari missed 14 games, as well.
Williams was a big reason for their success. Especially after Harris' departure, he was the team's go-to scorer, and he never shied away from the big moment.
Although it technically didn't count toward award season, Williams' performance in Game 2 of Los Angeles' first-round playoff series was evidence of that. The Clippers overturned a 31-point deficit against the Golden State Warriors, with Williams posting 36 points and 11 assists in 33 minutes.
Los Angeles' front office has done well to clear the decks for a run at a marquee free agent this offseason. According to Spotrac, the Clippers could have a little more than $54 million to spend.
Had the team struggled on the court, attracting a top name from a star-studded free-agent class might have been difficult. However, L.A. far exceeded expectations—with Williams playing a prominent role—and looks poised to take a big step forward in 2019-20.