The 32-year-old defenseman could have become an unrestricted free agent after this season. He has scored three points (one goal, two assists) in 37 games, missing 10 with an upper-body injury.
"It feels good," Bortuzzo said. "I'm excited. I'm glad they're putting a little more faith in me. It's no secret I love being here, I love being around this team and this organization. I'm excited it all came together pretty quick. It seemed like both sides wanted to get it done. The city's been amazing to me over the years. We've got a good squad here and it's just exciting to be a part of."
Bortuzzo has scored 66 points (18 goals, 48 assists) in 454 NHL games for the Pittsburgh Penguins and Blues. He won the Stanley Cup with St. Louis in 2019, scoring two goals in 17 Stanley Cup Playoff games.
"Keeping a guy like 'Borts' is important," coach Craig Berube said. "I think he's a great team guy. He provides an element that not a lot of people provide. He's a great, smart player. He does a lot of good things for us out there, great locker room guy. It's great to have him around."
St. Louis also signed Logan Brown to a one-year, $750,000 contract.
The 23-year-old center could have become a restricted free agent after this season. He has scored six points (three goals, three assists) in 17 games.
"'Brownie' came in here, went to the minors and put the work in, came up here and gave us some good games," Berube said. "I know he's in and out of the lineup now, but there's a lot of upside to him. I think it was a great signing."
Brown, the No. 11 pick in the 2016 NHL Draft and a St. Louis native, has scored 15 points (four goals, 11 assists) in 47 NHL games with the Ottawa Senators and Blues.
"It's definitely pretty cool, and now it's just being able to play and knowing I'm going to be here for another year," Brown said. "It's pretty cool and some weight off my shoulders. ... As soon as my agent called me and told me it was on the table, we kind of jumped on it. It's cool playing at home. When I knew I had that opportunity, I didn't have to think about it much."
St. Louis placed defenseman Scott Perunovich on injured reserve because of an upper-body injury and recalled forward
Dakota Joshua
from Springfield of the American Hockey League.
NHL.com independent correspondent Lou Korac contributed to this report