He then went abroad on a Fulbright fellowship and studied conducting, composition, and piano at the Stuttgart Staatliche Hochschule für Musik in Germany.
[2][3] Kapp started his musical career as a vocal coach at the Basel Stadttheater, Switzerland.
[2] Kapp and the Philharmonia Virtuosi also recorded a notable collection of three volumes of "Vivaldi's Favorites".
Kapp was the first of the original plaintiffs in Golan v. Holder, a 2012 United States Supreme Court that held that restoration of copyrights under the Uruguay Round Agreements Act was not unconstitutional.
[5] Kapp joined the case to oppose the restoration of U.S. copyright in orchestral public domain works such as Shostakovich's String Quartets, which Kapp had previously arranged while in the public domain, and which he would be unable to continue to exploit after restoration without paying royalties.