Cleveland Browns After going undrafted in the
2019 NFL draft, Gillan signed with the
Cleveland Browns. In the team's second 2019 preseason game against the
Indianapolis Colts, Gillan blasted a 74-yard punt. On 31 August 2019, he was named the starting punter for the Browns over veteran
Britton Colquitt. In Week 2, Gillan punted six times, five landing inside the 20 with a long of 47 in a 23–3 win over the
New York Jets, earning him
AFC Special Teams Player of the Week. After having 11 punts inside the 20 and only allowing 19 punt return yards Gillan was named AFC Special Teams Player of the Month in September. In Week 5, Jamie Gillan punted 7 times for 397 yards including a 71-yard punt that set a career long for Gillan. Gillan ended his rookie season with 63 punts for 2,913 yards (2,622 net yards) with 28 punts downed inside the 20 yard line which earned him a spot on the
Pro Football Writers Association All-Rookie team. Gillan was placed on the reserve/
COVID-19 list by the Browns on 30 July 2020, and activated from the list four days later. Gillan was waived by the Browns on 22 December 2021.
Buffalo Bills On 24 December 2021, Gillan was signed to the
practice squad of the
Buffalo Bills.
New York Giants On 7 February 2022, the
New York Giants signed Gillan to reserve/future contract and he became the lead contender to be the Giants' 2022 punter when the team released
Riley Dixon in March. He kicked several field goals in a preseason game against the Bengals following an injury to
Graham Gano, and made the 53 man roster. On 12 December 2022, while playing in a game against the
Philadelphia Eagles, Gillan was flagged for a rare illegal kick
penalty. While attempting a
punt, Gillan fumbled the snap and kicked the ball after it bounced off the ground. While
drop kicks are legal in the National Football League during a field goal, officials decided Gillan's kick was illegal and levied a 10 yard "Illegal kick of the football" penalty against the Giants. On 13 March 2023, Gillan signed a two-year, $4 million contract extension with the Giants. On 17 December, Gillian successfully kicked a 40–yard field goal against the
New Orleans Saints, in relief for injured kicker
Randy Bullock. In Week 18, Gillan punted five times with four inside the 20-yard line, in a 27-10 win over the Philadelphia Eagles, earning NFC Special Teams Player of the Week. On 8 March 2025, Gillan signed a three-year, $10 million contract extension with the Giants. In Week 3 against the
Kansas City Chiefs, Gano suffered a groin injury during warmups, causing Gillan to attempt an extra point during the game, which was blocked. On March 11, 2026, Gillan was released by the Giants. ==Personal life==