The 29-year-old, who has won 12 caps for the Wallabies, has agreed terms on a contract that will run up to the end of 2017 before returning Down Under to prepare for the start of the 2018 Super Rugby season.
The Cherry and Whites have decided to add him to their ranks amid fears over their strength in depth at hooker, with Richard Hibbard and Motu Matu'u their only senior options.
Hanson, who spent the majority of his career with Queensland Reds before joining Melbourne making 14 appearances for the Rebels last season, says he is looking to test himself in the northern hemisphere, while talking up the chance to work with Gloucester coach Johan Ackermann.
"I'm really excited to get involved where I can. I can see the enormous passion for the jersey, and I'm looking forward to being involved," said Hanson.
"Being coached by Johan Ackermann was a big part of why I was excited to come over here."
Gloucester were thought to be looking at Lions hooker Akker van der Merwe to improve the competition for places up front but director of rugby David Humphreys is happy to have added Hanson.
"James knows what it takes to perform on the top level, and he is excited to represent Gloucester and experience what life is like in the Aviva Premiership," he added.