After agreeing to leave his four-year spell at Deepdale and move to Wearside, Grayson said: “I’m delighted and excited by the opportunity to manage this club.
“I want to bring the good times back. Sunderland are so fortunate to have such tremendous support and I want to give these fans a team they can be proud of.”
Black Cats chief executive Martin Bain said: “From the outset he demonstrated a tremendous enthusiasm for the job and his desire and ambition to make this football club better shone through.”
Having led Preston to promotion to the Sky Bet Championship in 2015 and two successive 11th-place finishes, the club said: “We would like to place on record our thanks to Simon and Glynn for their hard work and service over the past four years.
“Current first team coach Steve Thompson will continue to look after first team affairs whilst this process in undertaken.”