[citation needed] On April 21, 2018, while on loan to Atlanta United 2, Carleton scored his first professional goal, a penalty kick in a 1–1 draw against Louisville City FC.

[7] In April 2021, Carleton joined Georgia Storm FC ahead of their first National Premier Soccer League season.

[10] Carleton returned to the professional game on March 9, 2022, signing with USL Championship side San Diego Loyal.

However, on the eve of the MLS Cup championship game, it was reported by local news media that Carleton had broken team curfew/rules and posted photos of drinking with friends in an Atlanta bar.

De Boer implied that Carleton needed to grow more in physical strength and should engage in a more substantial weight training and nutrition program.

On June 26, 2019, Atlanta United was one man short on the bench for an away match against Toronto FC due to Carleton forgetting his passport when the team met for the trip to Canada.

Two days later, manager Frank de Boer announced Andrew would play with the second team until he showed improvements in his professionalism.

Carleton finished out the match in which Atlanta United won 2–0 over Orlando, advancing to the US Open Cup Final for the first time in club history.

After the match it was reported that manager Frank de Boer stated that Carleton earned the minutes with his recent good play with the Atlanta United 2 reserve team and his work ethic during training.