Since parting company with Mercedes at the end of 2013, Brawn has been linked with multiple roles in the F1 paddock, most recently as a replacement for Martin Whitmarsh at McLaren.
But at a fishing event in Aberdeenshire on Saturday, Brawn declared that his F1 days were definitely over this time.
"What they didn't realise when I was invited here was they had a scoop because the world's press was trying to find out if I was retiring or not," Brawn was quoted as saying by the Daily Telegraph.
"This is the busiest time of the year for Formula 1 and I said I would come along and open the River Dee.
"If they had put two and two together they would have realised I was definitely retiring.
"I'm retiring - it's not tongue in cheek.
"I'm going to take a year to enjoy the fishing and then see what life brings.
"I'm looking forward to it but I've got no other plans."
Brawn previously took a sabbatical from F1 when he left Ferrari in 2006.
He had joined the Italian team after being one of architects of Michael Schumacher's title success with Benetton in 1994-95 and helped the German and Ferrari to dominate F1 in the early 2000s.
His last F1 absence ended when he returned with Honda for 2008 and ultimately took over the team to form Brawn GP when the Japanese firm pulled the plug on its involvement.
The Brawn team then swept to a shock 2009 title with Jenson Button (pictured) before transforming into the new Mercedes works outfit.
Brawn stayed on as team chief until last season, when a new structure headed by Toto Wolff and Paddy Lowe was implemented.
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- Martin Whitmarsh