The Lilywhites sold Wright to Bristol City in January 2017 with him in his final six months of his Deepdale contract.
Wright had joined North End as a 16-year-old after coming on trial from Australia.
Now 27, Wright has found appearances hard to come by with the Robins this season and has joined League One promotion-chasers Sunderland in search of a regular run of first-team football.
During his time with PNE, Wright made 205 appearances and scored eight goals. He was also in the Australia squad for the 2014 World Cup in Brazil.
There will be a couple of familiar faces for Wright at the Stadium of Light, with former PNE team-mates Aiden McGeady and Conor McLaughlin in the Sunderland squad.