"I was just being aggressive and made a play at the rim," Brown told reporters. "I'm not going to lie, it was pretty awesome. I'm not going to lie, yeah [it was on bucket list]."
The slam came in the third quarter of the Celtics' 139-107 win Monday at TD Garden in Boston.
The Celtics had a 79-63 lead when Brown caught a pass just outside the 3-point arc. Brown then darted into the toward the paint, while surrounded by three defenders. He picked up his dribble just as he entered the paint, as James slid under the rim to attempt to defend the Celtics star.
Brown disregarded "King James'" defense, jumping straight up while chest to chest with the Lakers star. James put up his arms to defend Brown, but was out-jumped. Brown finished the play by throwing in the dunk with both hands, as James stumbled away.
"That was a hell of a play by Jaylen. He is so gifted athletically," Celtics forward Jayson Tatum said. "I didn't think he was going to dunk it."
Brown had 20 points, six assists, four rebounds and three steals in the win. James had 15 points, 14 assists and seven rebounds for the Lakers.
"Why would I take it personally? It's part of basketball," James said, when asked about Brown's dunk. "You get blocks, you get dunks, you get crossed over at times, you get charges, it's all part of basketball."