The speedy half-back will now be a Bulldog until at least the end of the 2022 season.
“Jason is not only a key member of our playing group but a quality individual who is a big part of the future of the Western Bulldogs,” Bulldogs’ list manager, Jason McCartney said.
“To reach the heights he has after coming off the rookie list is a credit to not only his talent and work ethic, but at just 24, we think there’s also still plenty of improvement in him.
“We’ve seen ‘JJ’ grow in leaps and bounds over the past few years, and we’re looking forward to watching him continue to develop as a player and a person at our football club.”
Johannisen was recruited wick No.39 in the 2010 Rookie Draft and has gone on to play 79 career games since making his debut against North Melbourne in Round 19, 2012.
He shone to stardom in 2016, a career best season, where he averaged 24.3 disposals off half-back. He would also star in the Bulldogs’ finals campaign, where he adjudged the best player on the ground in the side’s shock win over Sydney on grand final day.
Johannisen has struggled under the weight of expectation at time this season, however, at just 24 years of age, his star is likely to only continue to rise.