Matthews initially joined up with the club on a short-term contract ahead of the 2019/20 campaign and from row man has become a valuable member of Danny Wilson's squad.
The hooker has shown a keen nose for the try-line throughout his rugby career to date; 29 tries in 26 matches for Sedgley Park in the 2016/17 campaign brought him to the attention of Boroughmuir, for whom he subsequently topped the Scottish Premiership try-scoring charts with 19 tries in 16 outings across the 2018/19 season before representing Boroughmuir Bears in the 2020 FOSROC Super6.
His try-scoring knack has also transferred to the professional arena, with Matthews crossing for six tries in 30 appearances for Glasgow Warriors.
Four of those scores have come this season, including a memorable score in the final minute of December's 22-7 win over Exeter at Scotstoun.
Born in Liverpool, Matthews qualifies for Scotland courtesy of his Glaswegian mother and has represented both Scotland U18 and Scotland Club XV.
Winner of the McCrea Financial Services Warrior of the Month award for September 2021, the hooker also holds the role of Commercial Manager at FOSROC Super6 side Watsonians alongside his Glasgow Warriors playing commitments.
Matthews told glasgowwarriors.org: I'm loving my time with Glasgow, and I'm really happy to re-sign with the club.
"It's a great place to play rugby. This season we've really developed and added to the blueprint and DNA of how we want to play, and you can see that from our league position and some of our performances this year.
"We've got a great culture, and I think with this group we're building towards something. Everyone here is mates and we've now got some great depth across the park.
"I'm excited for what's ahead and I'm looking forward to seeing how far we can go this season and for the future."
Head Coach Danny Wilson added: "Johnny has been a key member of our squad this season and we're delighted to secure his services for the future.
"After working hard during the off-season and pre-season, his game has taken massive steps forward and he's been a constant performer for us.
"We're looking forward to seeing more of him in a Warriors jersey."