Duncan attended Northern High School in Owings, Maryland for three years, before transferring to Saint Frances Academy in Baltimore, Maryland for his senior year.

[6] In January 2023, Duncan was invited to participate in both the 2023 Senior Bowl and the 2023 NFL Combine.

[11] As a rookie, Duncan appeared in ten games and started five in the 2023 season.

[12] Duncan appeared in four games at the beginning of the 2024 season, but he suffered a hamstring injury in Week 7 during his start against the Buffalo Bills.

[13] He was activated on December 23, playing one more game in Week 17 against the Jacksonville Jaguars.