McCrorie joined Bristol City at Ashton Gate in the summer of 2023 for around £2m and went on to make 89 appearances for the club, 41 of them last season.
In May, the Championship side triggered a one-year extension to his contract.
Capped twice by Scotland and selected for Euro 2024, McCrorie featured regularly at right-back for City but is comfortable across the defence and has also been deployed in midfield, the role he predominantly played during his first spell with Rangers.
He has been handed the number two shirt, vacated by long-serving captain James Tavernier following his departure after 11 years.
McInnes, who arrived from Hearts last week, noted that he had previously brought Ross to Aberdeen from Rangers and that the player was keen to prove himself at that time, which he felt spoke volumes about his character.
He said McCrorie has matured and improved, now brings greater experience, is a full international, and understands the club inside out.
McInnes added that their conversations showed a shared vision for the club, describing McCrorie as a determined, competitive presence on the pitch who is intent on helping bring success back.
McCrorie becomes McInnes’s first signing and will link up with fellow Scotland international Lawrence Shankland at Rangers this summer, with the striker currently at the World Cup.