The hooker joined Glasgow's Academy contingent ahead of the 2017/2018 season.
The 29-year-old returns to the club from FOSROC Super Series side Ayrshire Bulls, having been training with Franco Smith's squad at Scotstoun throughout the 2023/24 campaign to date.
A product of Strathaven RFC, the Carluke-born hooker made his professional debut away to Leinster in the 2016/17 Investec Champions Cup, going on to make 48 appearances across a five-year spell with the Warriors.
Stewart crossed for nine tries in those 48 appearances, most memorably scoring in the 2019 Guinness PRO14 Final at Celtic Park in front of over 47,000 spectators.
His form in a Glasgow shirt saw him called up to the senior Scotland squad for the first time ahead of the 2019 Guinness Six Nations, having previously represented his country at U17, U18, U19 and Club XV level.
He made his senior international debut at Scottish Gas Murrayfield in August 2019, coming off the bench against France in a Rugby World Cup warm-up Test at the home of Scottish rugby.
Stewart initially joined Connacht on a six-month contract in the 2022/23 season following his departure from Scotstoun, before linking up with Ayrshire Bulls.