The 39-year-old reached the impressive landmark by combining with Milan teammate Rafael Leao to open the scoring in the first-half of a 4-0 win against Crotone on Sunday.
Ibrahimovic added another, and goal No.501 by tapping into an empty net following Theo Hernandez's cross in the second-half.
The veteran striker has scored goals for fun for Malmo, Ajax, Juventus, Inter, Barcelona, Milan, Paris Saint-Germain, Manchester United and LA Galaxy over the years.
Ibrahimovic has scored 14 goals, along with Ciro Immobile and Romelu Lukaku, while Cristiano Ronaldo has 16 Serie A strikes for the season.
However, in the race for Europe's Golden Shoe, everyone is way behind Robert Lewandowski, who has scored 24 league goals in Germany's Bundesliga.
Ibrahimovic was not given the chance to complete his hat-trick at the weekend when he was replaced by Mario Mandzukic with 13 minutes remaining.
However, his goals, along with Ante Rebic's double, saw Milan maintain their two-point lead over second-placed Inter Milan in Serie A.
It remains to be seen when Ibrahimovic will hang up his boots, but his bosses at Milan would gladly keep him.
"Zlatan is happy with us and I think the best thing about this team is that the players are happy," manager Stefano Piolli told Sky Sports Italia after the game.
"We are with a huge club, everyone wants to do well and I think it's right that he continues playing, and that he does it with us.
"He is an athlete who is highly motivated, is scrupulous in the way he looks after his body with everything from diet to recovery.
"He's tired, but you don't stay at this level for this long without looking after yourself."
Zlatan Ibrahimovic has once again proven age is nothing but a number by surpassing 500 career club goals.