[6] After going undrafted in the 2019 NBA draft, Bigby-Williams was signed by the Charlotte Hornets but quickly released, instead joining the New Orleans Pelicans.

[10] He posted 18 points, 12 rebounds, six blocks, one assist and one steal in a loss to the Iowa Wolves on 23 January.

[12] On 27 February, Bigby-Williams was traded to the Fort Wayne Mad Ants in exchange for a 2020 2nd round pick and the rights of Isaiah Hartenstein.

[14] On 11 March 2021, Bigby-Williams left Cantù[15] and moved to Belgium in the Pro Basketball League, signing with the Antwerp Giants.

[17] On 1 February 2022, Bigby-Williams was re-acquired by the Fort Wayne Mad Ants of the NBA G League through his returning player rights.

[22] On 29 October 2024, Bigby-Williams signed with the Al Ahli Tripoli of the Libyan Division I Basketball League.

[23] In November 2024, Bigby-Williams linked with the NorthPort Batang Pier of the Philippine Basketball Association (PBA) as the team's import for the 2024–25 PBA Commissioner's Cup,[24][25] but he took an offer of trying out with the Jilin Northeast Tigers of the Chinese Basketball Association (CBA), NorthPort Batang Pier changed to tap Kadeem Jack.

[28] Bigby-Williams represented Great Britain in its Under-20 and Under-18 teams, averaging 8.9 points, 7.3 rebounds and 1.4 blocks per game between the two squads.