Buffalo Bills 2020 Gilliam was signed by the
Buffalo Bills as an undrafted free agent on April 25, 2020. He made the Bills' 53-man roster out of training camp as a replacement for veteran fullback
Patrick DiMarco, who was released by the Bills during the 2020 offseason. Gilliam made his NFL debut in the Bills' season opener against the
New York Jets on September 13, 2020. The following week on September 20, 2020, Gilliam caught a one-yard touchdown pass from
Josh Allen for his first career reception in a 31–28 win over the
Miami Dolphins. Gilliam finished the 2020 season with two receptions for 16 yards and a touchdown along with two tackles and a forced fumble.
2021 Gilliam finished the 2021 season with three rushing attempts for three yards, three receptions for 23 yards, and three tackles.
2022 On August 7, 2022, Gilliam signed a two-year, $5.2 million contract extension with the Bills. He caught eight passes for 69 yards and a touchdown and recorded three tackles.
2023 In Week 11 of the 2023 season, Gilliam was named
American Football Conference Special Teams Player of the Week after forcing a fumble on the opening kickoff. He finished the regular season with one reception for three yards along with three tackles and a forced fumble.
2024 Gilliam played in 15 games during the 2024 season and played 139 snaps on offense and 330 snaps on special teams. He recorded three rushing attempts for seven yards along with four tackles during the regular season.
2025 On March 11, 2025, Gilliam re-signed with the Bills on a one-year, $2 million contract.
New England Patriots On March 12, 2026, Gilliam signed with the
New England Patriots on a three-year, $12 million contract. ==NFL career statistics==