The Canadian flyer spent six years at the club after signing in 2009, before re-joining the club in March 2018.
With 54 tries in 123 appearances for the club so far van der Merwe sits clear at the top of Glasgow's all-time try-scoring chart, with his nose for the try-line and game-breaking ability making him a favourite of the supporters..
His try-scoring prowess proved to be an invaluable asset to the club in their pursuit of domestic glory; his try against Treviso in 2012 secured the first of five straight semi-finals in club history, whilst only Tommy Bowe can lay claim to having scored more tries in the history of PRO14 Rugby.
The pinnacle of van der Merwe's first spell at the club came in the 2014/15 season, with the Canadian writing his name into the club's history books. His dramatic late try against Ulster in the Guinness PRO12 semi-final helped to secure a place in the 2015 Guinness PRO12 Final, before touching down once more in the competition's showpiece event.
The winger continued where he left off upon his return to the club in 2018, scoring a brace of tries against Zebre at Scotstoun in his first match back in a Glasgow jersey.
He then helped Dave Rennie's side to the 2019 Guinness PRO14 Final at Celtic Park, becoming the first player to score 50 tries for the club along the way.
Van der Merwe also joined an illustrious list of players to have played in four Rugby World Cup tournaments at Japan 2019, whilst also holding the Canadian record for tries scored with 38 tries from 61 appearances.
"I couldn't have asked for a better place to start my career, and I couldn't have asked for a better return to the club," van der Merwe told glasgowwarriors.org.
"I'm proud to have been a part of this club's journey, from the days at Firhill to where we are today.
"I'm forever grateful for the opportunity Sean Lineen gave me at the start, as well as to Gregor Townsend and Dave Rennie for their faith in me. It's not a goodbye - it's a "see you in the future", because it's a special city and a special country.
"I'm still looking to play for another couple of years - I'm not ready to call it quits yet! - but I'm looking forward to keeping an eye on Glasgow from wherever we end up next."
Glasgow Warriors head coach Dave Rennie paid tribute to van der Merwe's contribution to the club, saying: "DTH is one of the best players to come out of Canada, and has the resume to back it up including winning two PRO12 titles and playing in four Rugby World Cups.
"He's a powerful, explosive and hard running winger with a massive work ethic.
"The importance of family and the close relationship with Warriors brought DTH back to Glasgow and he has been a major contributor to the club ever since.
"He's a top man and we wish DTH, Gill and the kids well in their next endeavour."
Glasgow Warriors Managing Director Nathan Bombrys added: "DTH is going to go down in club history as an all-time great of Glasgow rugby.
"Not only is he our all-time leading try-scorer, but the importance of some of the tries he scored proved just what a big-game player he is.
"His try away in Treviso in 2012 on his first game back from major injury sealed a place in the playoffs, and no fan will ever forget his return from hand surgery to score that try in the 2015 semi-final at Scotstoun.
"Off the field, too, he's been a true club man. Gill and DTH have hosted new arrivals to Scotstoun, for example, and he's built up a great relationship with fellow players and supporters.
"Any club that he joins will not only be getting a fantastic player, but an outstanding person. We hope we haven't seen his final match at Scotstoun, and we wish him, Gill and the children all the best for the future."