The 29-year-old returns to Scotland after a season with Perpignan in the French Top 14, having spent 11 years at Edinburgh prior to his stint abroad.
He has signed a two-year deal with Franco Smith's Glasgow Warriors, and joined up with the squad for pre-season training last week.
In his first interview as a Glasgow player, Ritchie said: "For me, seeing the success Glasgow have had over the last few years is a huge motivating factor in wanting to join the group.
"The way they play rugby will suit how I like to play and hopefully I can contribute really well here."
He is eager to make his mark in Smith's squad, having been impressed by Glasgow's attacking prowess during his time with Edinburgh.
Ritchie said: "The biggest thing that comes to mind when I think about previewing Glasgow whenever we came to play them is it was always the threat they had with ball in hand.
"So, for me, I'm really excited to be part of that."
The former Scotland captain believes his skills align well with Glasgow's style and hopes to bring added value to the team. Ritchie said: "I pass the ball well, so when we're in those forward pods, that part of my game can hopefully contribute well.
"Also around the breakdown, Glasgow have always been a huge threat off turnover ball, so hopefully I can try and get a few turnovers and see if we can score some points from that."
He will also be reunited with several well-known faces at Scotstoun, including Scotland internationals Matt and Zander Fagerson and George Horne.
Ritchie said: "I was at school with Matt, Zander and George.
"George and I have known each other since we were super, super young. Hazel [mum of Pete and George Horne] used to be my tennis coach when I was about four years old so I've known the Hornes for a long time.
"I lived with Ally Miller when we were coming through at Edinburgh. There are lots of guys in there that I'm super excited to be back seeing on a regular basis."
Having previously visited Scotstoun as an opponent, Ritchie is now eager to experience the stadium's atmosphere as a home player. He said: "It's always a great atmosphere here at Scotstoun.
"Being on the other side of it, maybe you don't necessarily enjoy some of the heckling that you get, but I'm looking forward to them being on my side for sure."