The former Harlequins player, who has played for England, has held previous coaching roles at Ipswich School, Rosslyn Park, Northampton Saints, Wimbledon and Westcliff.
He is part of the coaching team within the Harlequins Academy programme, a role he will continue alongside his Worthing Raiders and wider club responsibilities.
It comes after the Raiders announced they were parting company with their coaching team of Jody Levett, James Arthur, Ben Coulson, Jack Emmerson and Ian Davies with news there will be no league season for rugby in 2020-21. Coulson will remain connected with Worthing supporting the juniors and Raiders academy programme.
Turner-Hall said: “I firmly believe Worthing Raiders are a sleeping giant within the National League. They have always played an exciting and attractive brand of rugby and I will look forward to improving the defensive mindset and culture.
"There is everything here to take the club beyond expectations. I see this extended break as a fantastic opportunity to develop and strengthen the squad.
"Worthing has always been the shining light in Sussex and I’m looking forward to working with local talent in my home county.”
René Draude, director of rugby, said: “As we look to build for a bright future it’s with great pleasure we welcome Jordan to Worthing RFC as head coach for the Raiders.
"Acknowledging the hard work put in by the former coaching team, Jordan will bring a new energy and enthusiasm to drive the Raiders and wider club forward.
"Although in uncertain times presently, I’m extremely excited at the prospect of working with Jordan in what will for sure be an exciting journey for Worthing RFC.”