At South Carolina, Shell made 47 consecutive starts, which is tied for the second-most in school history. His college career got off to a strong start, as he was named to the Freshman All-SEC team. Over his tenure, he primarily played right tackle before switching to left tackle for his senior season.
Shell was selected by the New York Jets in the fifth round of the 2016 NFL Draft. He played four seasons for the franchise, starting 40 games. During the 2020 offseason, he signed with the Seattle Seahawks. He spent two years in Seattle.
Last season, he played for the Miami Dolphins. He began on the practice squad, but he ended up starting 11 games. In 761 offensive snaps, he allowed two sacks and recorded four penalties. He posted an overall PFF grade of 64.9.