She will take up the job of managing partner at integrated marketing agency Kindred next week.
Oliver worked behind the scenes for more than a year to get Jolly Rebellion, owned by Nexus Communications Group, off the ground before its public launch in August 2017.
The agency promised to abandon traditional industry silos with a fresh approach to working with clients, by bringing PR, advertising and digital together at the start of each process.
Oliver told PRWeek: "My position as the MD of Nexus Communications Group unfortunately became untenable and I decided to leave. My decision to leave the Nexus Communications Group is in no way a reflection on Jolly Rebellion and the fantastic founding team I’ve had the pleasure of working with over the last year. I wish the team at Jolly Rebellion and Nexus every success in the future and am so proud of what we achieved together."
At Kindred, whose clients include the Home Office, The Fox Entertainment Group and SsangYong, Oliver will report to the agency’s chief executive, Nick Mustoe.
She said Kindred had an "impressive" track record on behaviour change campaigns and had "moral backbone and integrity".
Oliver, an industry veteran who has worked in PR and comms for 25 years, also co-founded Fever, owned by Nelson Bostock Group, and was brand lead at Trimedia (now Grayling) for more than seven years.
Mustoe said of Oliver: "Her mission to integrate advertising, PR and digital together to give brands brilliant ideas that can live everywhere fits very well with Kindred’s view of the world."