John Kruse began his studies at the Carl Nielsen Academy of Music in 1980 with solo clarinetist Jens Schou. In 1984 he continued his studies at Music Academy in Paris with Professor Guy Deplus. In 1987, John Kruse joined the Royal Danish Orchestra where he was employed until 1989. That year, John Kruse was appointed solo clarinetist in Odense Symphony Orchestra. From the summer of 2005, John Kruse was appointed 1st solo clarinetist in the Royal Danish Orchestra.
John Kruse has recorded several CDs, including newly composed Danish music for clarinet, Messiaen's "Quartet for the End of Time", Mozart's complete music for basset and recently Mozart and Nielsen's concertos for clarinet and orchestra.
John Kruse has received the Jacob Gade-scholarship and Holger Bruusgaards Grant. He has served on the jury of the first four Carl Nielsen International Clarinet Competitions.
John Kruse has been a soloist with the Royal Danish Orchestra, Copenhagen Phil, Odense Symphony Orchestra, Danish National Symphony Orchestra and the Czech Chamber Orchestra.
John Kruse has continuously sought further inspiration from international figures such as Michel Arrignon professor at Music Academy in Paris and His Deinzer, former professor in Hannover.