On 17 September 2008, it was announced that Southern FM was one of 30 local radio stations to face a re-brand to Heart within the next 18 months.

Under the leadership of managing director Keith Belcher and programme director Rory Macleod, early presenters included Sean Bolger, Louis Robinson, Stewart Macintosh, Vince Geddes, John Mann, Russ Williams and Becky Manesseh.

The head of news at launch was Paul Woodley with a reporting team including Andy Steggall, Andrew Winter and Cornelius Lysaght.

Tommy Boyd joined the station, initially as a fill-in for Timbo (Tim Lloyd) and was subsequently hired to present a regular Sunday evening show with a team of assistants including Nicky Keig-Shevlin.

Radio House, Portslade, the previous home of Southern FM and recently a broadcasting station for Heart Sussex, was put on the market in 2019.