She joined the agency in early 2015 after stints at The Academy, Unity and Mischief.
Vardon (pictured), who left Golin on Friday last week, said: "After almost four years at Golin, I’ve decided it’s time to move on. My aim when I started was to build the creative culture of the agency and improve the quality of work across teams - and I’m pleased I’ve been able to do that.
"I’m now looking forward to a new challenge, working with other agencies over the next few months and splitting my time freelancing between London and Brighton."
Golin London MD Bibi Hilton said: "Gemma has decided to leave her permanent ECD role at Golin to return to freelancing. She has made a huge contribution to Golin in her four years here and we look forward to that continuing in a freelance role next year."
Vardon is a mentor on the new Creative Mentoring Project from PRWeek and the PRCA Creative Group.
Earlier this month, Golin announced a global "repositioning" in which it "proudly" calls itself a PR agency.
PRWeek reported in February that a number of senior figures had left Golin’s London office, including marketing and talent lead Jane Fordham and head of digital Alex Brittain.
The agency was 18th in the PRWeek UK Top 150 for 2018.
