Despite being just 16 years old, he was given his league debut in Grasshoppers's first match of the 2007–08 season, a 2–0 victory over FC St. Gallen, playing 90 minutes at right back.

He played for Parma's primavera in the 2011 edition of the Torneo di Viareggio, but made just two league starts and a substitute appearance for the first-team in his debut season.

In June 2012, Calcio Padova confirmed that Feltscher had signed on a loan deal from Parma with an option to buy for the year 2012–13.

[9] In September 2017, Feltscher spent ten days on trial with EFL Championship side Birmingham City,[10] being told that a potential permanent deal was "on the table".

[14] On 19 December 2017, Feltscher signed with Major League Soccer side LA Galaxy ahead of their 2018 season.