Watch: Will Smith celebrates Oscar win by Gettin' Jiggy With It on the dancefloor
Smith, 53, attended the Vanity Fair Oscars afterparty with his wife and children, where he was filmed dancing and singing along to his 1998 chart hit, cheered on from the sidelines by wife Pinkett Smith.
The Fresh Prince Of Bel-Air star scooped the award for his performance as Richard Williams — the father of tennis champs Venus and Serena Williams — in King Richard.
It is the third time the Men In Black actor has been nominated for Best Actor, having previously been nominated for Mohammed Ali biopic Ali in 2002 and The Pursuit of Happyness in 2007.
Smith had his Oscar clasped in his hand as he took centre stage on the dancefloor and celebrated his win, while the crowd joined him in singing along to his own song.
He attended the party with with Pinkett Smith, 50, and their children - 21-year-old daughter Willow and 23-year-old son Jaden.
The King Richard star has become the talk of Oscars night after he slapped Rock live on stage at the awards ceremony for making a joke about his wife.
Rock, 57, who was on stage to present the award for Best Documentary Feature, made a comment about Pinkett Smith possibly starring in a sequel to G.I. Jane due to her bald head.
Pinkett Smith has spoken openly in recent years about losing her hair due to alopecia and seemed to roll her eyes in reaction to the gag.
Smith then approached Rock on stage and hit him in the face, shocking the comedian before returning to his seat.
Viewers in the UK and other countries then heard Smith yell at Rock several times to, "Keep my wife's name out of your f***ing mouth", while the US broadcaster cut the audio.
The Los Angeles Police Department has said it is not currently investigating the incident.
Smith went on to take to the stage after being named Best Actor and delivered an emotional speech through floods of tears, in which he apologised for the incident, ending with the words "I hope the Academy invites me back".
The Academy said in a statement that it does "not condone violence of any form."