Williamson attended the University of Maryland, where he played in the 2015–2017 seasons, appearing in 58 matches and scoring 14 goals.

[3] Williamson was a member of the D.C. United Academy, and therefore not eligible for the MLS SuperDraft, before being traded to the Portland Timbers in January 2018.

[6] He made his professional debut as a member of Portland Timbers 2 on April 4, 2018, against Tulsa, and scored his first goal on May 12 of that year against Tacoma.

[8] On January 15, 2025, Williamson was dealt to Charlotte FC in exchange for $100,000 in General Allocation Money.

[11] He made his debut with the senior national team on July 11, 2021, in a Gold Cup game against Haiti.