The 39-year-old defensive lineman is expected to earn about $5.5m in Baltimore after recording 6.5 sacks for Arizona last season.
Campbell, who played for the Ravens from 2020 to 2022, fills a need on the defensive front after Baltimore's pursuit of another impact addition fell through.
He enters his 19th NFL season with 117 career sacks, while the Ravens seek depth amid uncertainty over Nnamdi Madubuike's recovery from a neck injury.
Is Campbell's return a savvy move or a patch for Nnamdi Madubuike's uncertain future?
Can a 40-year-old legend, a new coach, and an injured star fix the Ravens' broken pass rush?