Blythe stepped up to lead Gesh in September last year and was previously the managing director of Epsom and St Helier Hospitals for four years.
He has more than 20 years' experience in the NHS, having started his career as a management trainee at the Royal Berkshire Hospital in 2004.
Oke Eleazu, trust chair, said: 'James is coming full circle as he started his career in the NHS at the Royal Berks as a graduate trainee in 2004.
'He brings with him a vast amount of experience and expertise gained from more than two decades of leadership roles within the NHS which we will embrace and benefit from as an organisation.'
Blythe added: 'It is an enormous privilege to be appointed to the CEO role at the trust. Over the last few weeks, I've come to appreciate the exceptional culture, drive to innovate and focus on patient care that makes RBFT so special, and I'm really excited to work with the team to ensure this continues and goes further.'
Blythe will start later this year when Steve McManus steps down after more than 9 years in the role and more than 38 years service with the NHS.
Dr Matthew Shaw will join Gesh as chief executive in April from Great Ormond Street (GOSH).
