A no nonsense second row forward, he made nearly 300 appearances for his beloved home town club.
After winding up his playing career with a couple of seasons at Bedford, he joined the Gloucester coaching team under Phillipe Saint-Andre before taking the Director of Rugby role at Worcester Warriors.
He helped guide the Warriors into the Premiership for the first time in their history before moving down the M5 to Bristol Rugby as forwards coach.
Gloucester Rugby, however, was his spiritual home and he returned to Kingsholm in December 2010 in a scouting capacity before taking on the role of Rugby Operations Manager ahead of the 2011-12 season.
Talking to the Gloucester Citizen, Walkinshaw admitted that Brain's passing had come as a huge shock:
"When Ken (Nottage) told me the news I could barely believe what I was hearing.
"We are all incredibly saddened by his passing, and it is far too young an age to pass away. It's been a massive shock.
"John was a true legend of the Gloucester club, not just for his outstanding time as a player, but also for his two stints with coaching the club.
"He was a very switched-on character, he loved the club and cared deeply about it."
Walkinshaw also stressed that the club will help John's wife and daughters in whatever way they can.
"The club's situation is irrelevant - what matters now is John's family.
"Our condolences go out to his family, and we will do all we can to help them through this difficult time.
"John was a fit and healthy guy, he will be sorely missed at Kingsholm.
"Our thoughts are with John's family, and that's what is important for us at this time."