The Italy Under-21 international right-back has put pen to paper on a fresh six-year deal, running until the summer of 2032, which includes a club option for a further year.
"Signing a new contract at the club is an amazing sensation, so I'm really happy," said Kayode, who was nominated for the Premier League Young Player of the Season award following an impressive 2025-26 campaign.
"I feel like this club is a family, so I wanted to continue my journey here.
"I have amazing relationships that make me really like coming in for the morning to train and have fun with my team-mates, the staff and all the people around.
"Ever since I joined the club, everything has been amazing. It feels like I've been playing for Brentford for 10 years.
"I've improved a lot on the pitch and outside of the pitch. That's really important for me."
Kayode's initial move to west London was a loan from Serie A side Fiorentina, which was made permanent in May 2025.
He missed just one Premier League match last season, making 37 appearances across all competitions and playing more than 3,200 minutes for the Bees.
Brentford head coach Keith Andrews praised the defender's development since his arrival at the club.
"Michael had an amazing season last year," Andrews said. "He epitomised everything good that we do. His development and evolution has been really, really impressive.
"We're absolutely delighted that he wants to stay because we love having him here, and this new contract is absolutely deserved.
Looking ahead to next season, which will be his second full campaign at the club, Kayode added: "I think about it every minute. I can't wait to start again."
The defender has established himself as a key figure in Brentford's backline since arriving from Italy, with his performances last season earning recognition among the division's best young players.
His new deal ties him to the club for the long term and represents a significant vote of confidence from Brentford in a player they view as central to their plans, both on and off the pitch, as they look to build on last season's progress.