The Panthers signed Stewart to a contract Wednesday, Myles Simmons of the team's official site reports.
Stewart was let go by the Packers in mid-August after signing with the team as an undrafted free agent out of Michigan State. In his career with the Spartans, the 24-year-old racked up 150 receptions for 1,640 yards with seven touchdowns. He'll look to earn a depth or a practice squad roster spot for the 2020 season.