The 22-year-old made his Magners League debut this season and has gone on to make five league appearances.
Nashville-born Seymour, qualifies for Scotland through his mother and moves to the Warriors in the search of regular rugby.
He has penned a two-year deal to join the Scottish side in the summer as a direct replacement for Max Evans, who has signed for Castres.
"I'm just taking things one step at a time, but I feel I will be in the right place to develop as a player and to strive towards representative honours," said Seymour.
"I'm very keen to establish myself as a Magners League player.
"I've always been attracted to Scotland because of the style of rugby they play and the expansive role of the backs."
Glasgow head coach Sean Lineen reckons the opportunity to play regular rugby will see Seymour flourish and become a major player in the absence of the Warriors' World Cup stars.
"He's a guy who wants an opportunity and we can give him one," said Lineen.
"Being behind two international class wingers doesn't mean he's a bad player. He's a young lad who just wants an opportunity.
"We've had a look at his game and he's a quick player. He's really enthusiastic and I believe he will bring a real edge to our outside backs.
"He's a lad with a lot of talent, he's Scottish qualified, and he's raring to go.
"It's a big season for us next season when a lot of our players could be away at the World Cup. It's a chance for other players to shine."
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