The striker has committed to Blues until the summer of 2022, at least.
The 30-year-old's previous deal was due to expire at the end of this season.
Jutkiewicz's contract extension comes on the back of the most productive season of his career.
He bagged 14 goals in 2018/19 – the highest return from any of his 13 years in professional football.
The August 2016 signing from Burnley also provided 10 assists last term, putting him in the top 10 in the table of goal providers in the Championship.
Jutkiewicz earned EFL Player of the Month honours and was also ranked number one in the division, under the WhoScored.Com player rankings.
Jutkiewicz has continued in the same vein during pre-season, notching twice in three appearances including the winner at Bristol Rovers on Saturday.