[2][3] Seggerman won his first ITF singles title in 2023 at the M25 Monastir tournament, defeating Ilia Simakin, 7–5, 6–4 in the final.

[4] With fellow American Patrik Trhac, the duo won eight consecutive ITF doubles titles between July and October 2023.

[citation needed] Seggerman reached the main draw as a qualifier at the 2024 Lexington Challenger, rising into the top 400 for the first time.

[citation needed] Seggerman and Trhac received a wildcard to the 2024 US Open, making their Grand Slam debut.

[citation needed] Seggerman began his 2025 campaign with a doubles title at the 2025 Canberra challenger, partnering countryman Eliot Spizzirri.

The pair saved a championship point in their title match win over Pierre-Hugues Herbert and Jérôme Kym.