Brogdon edged out New York Knicks guard Immanuel Quickley for the award, garnering 60 out of 100 first-place votes and compiling 408 total points, ahead of Quickley's 34 first-place votes and 326 total points in what is likely to be one of the closer races in this year's slate of awards.
"This is such an honor. It's definitely been a transition for me, coming from Indiana to Boston," Brogdon said in an interview on TNT's "Inside The NBA" as part of the award announcement. "But I'm with a great organization, I have great teammates, a great coaching staff. Joe [Mazzulla] has taken over and done a great job, so I want to thank those guys."
Quickley, who averaged 14.9 points, 4.2 rebounds and 3.4 assists this season for New York, was part of a second unit that was a constant in the Knicks' success this season under coach Tom Thibodeau -- especially after the arrival of swingman Josh Hart prior to February's trade deadline.
That second unit helped power New York to the fifth seed in Eastern Conference, putting the Knicks back in the playoffs for the second time in three years -- and just the second time overall in the past decade.
Boston acquired Brogdon last summer to give the Celtics another downhill offensive attacker and creator after they saw their offense bog down at times in last year's playoffs, particularly in their NBA Finals loss to the Golden State Warriors.
After starting every game he played the previous four years with the Indiana Pacers and Bucks, Brogdon came off the bench for all 67 games he played this season for Boston.
"I had the pleasure of playing with Giannis [Antetokounmpo], one of the best players in the world," Brogdon said. "For me coming out of college, I was an All-American, I had good accolades, but you have to check your ego at the door, especially when I got to Milwaukee. Then I went to Indiana, and me and [Domantas Sabonis] are running the show there, and my last two years there weren't super successful.
"So for me, that was another gut check for me, in understanding maybe I'm not a No. 1 guy. But I can be a No. 2, 3 or 4, and then coming to Boston, playing behind [Jayson Tatum] and [Jaylen Brown] and these guys, proven All-Stars and soon-to-be All-NBA guys, it's been a good fit for me."
The 30-year-old guard did just that for the Celtics, averaging 14.9 points, 4.2 rebounds and 3.7 assists while shooting 48% overall and 44% from 3-point range in helping the Celtics finish with the NBA's second-best record behind the Bucks.
Brogdon also becomes the second player to win both Sixth Man of the Year and Rookie of the Year, joining Mike Miller with that distinction.
Brogdon's being named Sixth Man of the Year marked the fourth NBA award to be handed out in as many nights, after Sacramento Kings coach Mike Brown was named the league's Coach of the Year on Wednesday, De'Aaron Fox was named its inaugural Clutch Player of the Year on Tuesday and Memphis Grizzlies forward Jaren Jackson Jr. was named Defensive Player of the Year on Monday.
The league is expected to announce another round of its season-long honors next week.