Mandy Pearse has set up Seashell Communications after more than 12 years with the council.
A spokesman for Exeter City Council said the authority was currently reviewing its PR and comms functions as part of a wider restructure.
Pearse said: 'Budgets are reducing the scope for doing some of the more challenging work at the moment.
'I felt it was a good time to move to a wider variety of work and focus more on marketing and comms, rather than the corporate management role I have often had to play on major projects.'
Before her time at Exeter, Pearse worked at Lewes District Council as head of publicity and marketing for five years. She is currently serving on the CIPR Local Public Service Committee.
Seashell Communications will operate from her home in Teignmouth and offer PR support and training services to organisations across the South West.
Pearse, who is involved with a number of local authorities in Devon, will also offer services to similar organisations across the country.