The shot was the first game-winning buzzer-beater of Williams' 14-year career and lifted the Clippers to a 119-116 victory at Staples Center.
"I get made fun of that I don't know how to celebrate," Williams told reporters. "My teammates say I don't know how to celebrate. I've been working on my [celebrations]. They say I don't show emotion."
Williams caught a pass from Danilo Gallinari after the Clippers inbounded the ball from the left flank on the final possession. He used a slight screen from Gallinari to create a little space before being smothered by two Nets defenders.
Williams still decided to launch a shot from about 30 feet away, heaving the ball up over the defense with the score tied at 116-116.
The final buzzer sounded as the ball slid through the net, giving the Clippers a narrow home victory.
"Lou is a professional scorer," Clippers forward Montrezl Harrell said. "When he got the ball in his hands, we had two great options ... he took the shot he felt was a good shot on a good pull-up and we live with it."
Williams scored 25 points off the bench to lead the Clippers. The Sixth Man of the Year candidate also had six rebounds in the win. D'Angelo Russell scored a game-high 32 points and had 10 assists and five rebounds for the Nets.
The Clippers host the Indiana Pacers at 10:30 p.m. Tuesday in Los Angeles.