Walkinshaw, Gloucester's majority shareholder and son of the late Tom Walkinshaw, replaces David McKnight, who is stepping down as the club's non-executive chairman after 18 months in the position.
McKnight, who took up his post in January 2011 when the Gloucester board was revamped following the death of chairman and owner Tom Walkinshaw, will remain as a non-executive board member at Kingsholm.
McKnight said: "I'm delighted that Ryan is now in a position where he can take over as executive chairman.
"My role was only ever a caretaker one when Tom sadly passed to try and help Ryan acquire the knowledge base required to lead this area, Gloucester Rugby, of Tom's business empire.
"My remit was to help run the company within a defined corporate structure but the club is in great shape now, and Ryan is in a great position to take the club forward on a day-to-day basis, which is what is required."
Walkinshaw said: "The last 18 months have been an extremely steep learning curve but extremely fulfilling at the same time. It's been hard work but I'm enjoying it.
"We've had some change here at the club in the past few months but I genuinely think we've a really exciting future ahead of us."
Earlier this month Gloucester named Nigel Davies as the club's new rugby director, succeeding Bryan Redpath.
It was also announced last week that managing director Ken Nottage would be leaving later this summer after 13 years with the Aviva Premiership outfit.