The 30-year-old makes the switch to Scotstoun following six seasons at Edinburgh. He initially joined Edinburgh on a one-year deal having caught the eye for Crusader Knights, the development squad of Super Rugby's Crusaders.
Born in Christchurch but Scottish-qualified by virtue of his Stirling-born grandfather, the Shirley Boys High School alumnus quickly established a reputation for his scrummaging prowess as well as adding a physical carrying presence to the Edinburgh front-row.
The tight-head has made 89 appearances to date for the capital outfit, including the 2018/19 Heineken Champions Cup quarter-final against Munster and the 2019/20 Guinness PRO14 semi-final clash with Ulster.
Berghan will have the opportunity to add to his 28 caps in a Scotland jersey over the course of the next six weeks, having been selected amongst Gregor Townsend I'm playing group for the 2021 Guinness Six Nations.
A mainstay of Scotland squads since his international debut against France in 2017, he started two of the most famous Scottish victories of the last decade - 2017's 51-24 domination of Australia at BT Murrayfield and the 2018 Calcutta Cup victory over England - in addition to being selected for the 2019 Rugby World Cup in Japan.
His most recent Scotland appearance came in the inaugural Autumn Nations Cup, starting against France at BT Murrayfield back in November.
Speaking about his impending move to Scotstoun, Berghan told glasgowwarriors.org: "Danny [Wilson] gave me a call and outlined what he's looking to build at Scotstoun over the next few years, and it sounds like a really exciting time to get involved with the club.
"Everyone talks about the culture of the club and for my partner and I it seemed like a really sensible and exciting move.
"I've got to admit, the Scotstoun crowd is always incredible. Every time I've come through as an Edinburgh player the noise has been unbelievable. Players, coaches, even friends and family all talk about how incredible the atmosphere is for a Glasgow home game and I can't wait to be a part of that in the near future.
"I know a few of the boys from Scotland camps, but I'm also really looking forward to meeting the rest of the squad, as well as the coaches and backroom staff for the first time.
"The quality of the front-row players at Glasgow is unreal; with Jamie [Bhatti] coming back to Scotland next season too, you can make two, nearly three, front-rows full of international players. There's going to be a lot of competition for places and a challenge I'm looking forward to. It's an exciting prospect, and I want to put my best foot forward and show what I'm all about."
Glasgow Warriors Head Coach Danny Wilson was delighted to secure the services of the tight-head, saying: "Adding a player of Simon's calibre to our pack is a massive boost for us going into the 2021/22 season.
"He's a proven performer at both club and international level, and his work ethic will make him a valuable asset to our front-row.
"I've worked with Simon previously in Scotland camps - he's a very athletic tighthead prop and he's got a wealth of experience that will also benefit our young front-rowers."