Youth and college Semmle played as part of the
Karlsruher SC academy from 2012, appearing for the club's second team in the
Oberliga Baden-Württemberg and making a single senior appearance in the
Baden Cup in 2018. In 2018, Semmle moved to the United States to play
college soccer at
Barton Community College where he made seven appearances for the Cougars. In 2019, he transferred to
Monroe College, making 12 appearances and only conceding two goals during the entire season with the Mustangs, helping lead Monroe to its first ever NJCAA Division I Men's Soccer Championship. Semmle again transferred colleges in 2020, joining
Marshall University. In his junior season, Semmle played all but 45-minutes of the Thundering Herd's national title campaign, leading the NCAA with eleven shutouts while holding a 0.380 goals against average. In his three seasons at Marshall, Semmle was named Conference USA Goalkeeper of the Year, the Conference USA Golden Glove Award, First-Team All-Conference USA, 2021 United Soccer Coaches All-Southeast Region Third Team and 2021 Second Team All-Conference USA.
Professional On 21 December 2022, Semmle was selected 41st overall in the
2023 MLS SuperDraft by
Colorado Rapids. However, he went unsigned by the club. On 15 February 2023, Semmle signed with
USL Championship side
Louisville City ahead of their upcoming season. He made his debut for Louisville on 18 March 2023, starting in a 1–0 against
Monterey Bay. Semmle tied for the most shutouts (13) in the 2023 season (12 shutouts in regular season and 1 shutout in playoffs). On 31 January 2024, Semmle was acquired by the
Philadelphia Union via a transfer with
Louisville City after the Union acquired Semmle's college protection rights from
Colorado Rapids. On 30 December 2025, Semmle was signed by
Lexington SC via a free transfer. == Honours ==