The 21-year-old, who was already locked in for next season, agreed to terms on Tuesday, with the new deal taking his tenure through until at least the end of 2029.
The extension follows an impressive three years for the key forward, who won a VFL premiership in his first season at the club, and also made an immediate impression at senior level.
The 194cm van Rooyen was last year named best young player at Melbourne's best and fairest awards ceremony.
Originally from Perth, van Rooyen became a Demon when he was taken at pick No.19 in the 2021 national draft.
After making his debut in 2022, van Rooyen quickly established himself as a cult hero, with Demon fans chanting "Roo" when he touches the ball.
He has played 26 games for the Demons, kicking 36 goals along the way.
Melbourne list manager Tim Lamb said the contract extension was great news for the red and blue.
"Jacob has applied himself terrifically since arriving at the club, and we are continually impressed by his attitude and eagerness to learn," Lamb said.
"He is a much-loved character, both within the club and among our members and supporters, and at just 21 years old has an exciting future ahead.
"We have seen the impact Jacob can have at AFL level, and we look forward to hearing the 'Roo' chant around the MCG for many more years to come."
11°C