"The squad gets stronger each year and reaching the PRO12 final for the first time last season shows the progress the club is making. I know I'll have to work hard to get into the team.
"I'm looking forward to playing at Scotstoun regularly in front of very passionate supporters. The atmosphere at
the play-off was incredible.
Warriors head coach Gregor Townsend believes Downey's addition will help his side make further progress as a squad next season.
"He is a tough defender and brings real physicality when carrying the ball.
"He has a lot of experience having played for Northampton and Munster, and has been involved in some epic European games."
Following an initial three game period with Munster in early 2006, Downey then spent five highly successful years with Calvisano and Northampton Saints, returning to Munster on a two-year contract at the start of the 2012/13 season.
In that time the centre made 47 appearances for the province and also went on to make his Irish senior debut against Canada on the North American tour in June 2013.
See pictures of Downey's time at Munster by clicking here.
He will link up with his new team mates for the first time at a pre-season training camp in France next week.
<blockquote class="twitter-tweet" lang="en"><p>Thank you <a href="https://twitter.com/Munsterrugby">@Munsterrugby</a> <a href="https://twitter.com/MRSC16">@MRSC16</a> <a href="https://twitter.com/MRSCLondon">@MRSCLondon</a> <a href="https://twitter.com/MRSCDublin">@MRSCDublin</a> <a href="http://t.co/bqF3JTU0it">pic.twitter.com/bqF3JTU0it</a></p>— James Downey (@jamesdowney23) <a href="https://twitter.com/jamesdowney23/statuses/482475057269456896">June 27, 2014</a></blockquote>
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