[1] Rosen began his professional career as a swing musician for the bass, guitar, and percussion tracks of 13.

[1] Rosen can play about 70 musical instruments including the "flugelbone", melodica, Fender Rhodes, and theremin.

[1] Of these he has described the flugelbone as his "orchestrating secret weapon" due to its ability to utilize variety of timbres.

However, he considers himself primarily a bassist but uses the range of instruments in his repertoire to improve the quality of the music he is able to create.

[9] The band won a Grammy Award for an arrangement for the song "Meta Knight's Revenge", from the game Kirby Super Star (1996), in 2022,[10] and were nominated again in 2024.