Starting in 2018, Wälti played for Pittsburgh Panthers, playing all 19 games of the season and scoring one goal against NC State Wolfpack.[2] Wälti played 20 games in 2019, also scoring against Duke University.[3] Wälti played every minute of every game in te 2020–21 season, joining teammate Nico Campuzano as the only two players to do that. Wälti scored 1 and assisted 3 that season.[4][5] In the 2021 season, Wälti scored 1 goal for Pitt in the NCAA men's soccer tournament second round against Northern Illinois.[6] Additionally, Wälti played every game of that season.[7][8] In 2022, Wälti helped Pittsburgh defeat NC State by scoring his second goal of the season.[9]
After the 2022 season with the Panthers, Wälti signed with MLS Next Pro side Austin FC II.[11][12] However, Wälti would only play 12 games in the first half of the MLS Next Pro season before being transferred to Colorado Rapids 2 in the same league.[13][14]
Wälti got his first MLS Next Pro assist in the 6–2 victory over Whitecaps FC 2.[15] At the end of the 2023 season, Wälti's option for 2024 was not picked up.[16][17]
Pittsburgh Riverhounds
In January 2024, Wälti signed with USL Championship club, Pittsburgh Riverhounds after his 8 appearances with Colorado in the 2023 season.[18][19] Wälti played his former club, Pittsburgh Panthers, in a preseason game with the Riverhounds, which they won 2–0.[20] Wälti made his official debut in the 1–0 loss away to New Mexico United, which Wälti started.[21] Wälti scored his first professional goal in the 2–2 draw with the Colorado Springs Switchbacks.[22] He scored once again against the Tampa Bay Rowdies, though it would eventually result in a 2–1 loss.[23]