Johnsen's compositions consisted primarily of dramatic works, opera and ballet, as well as vocal music and instrumental keyboard music. He was well versed in the use of German texts which may indicate his national origin; he was in Sweden serving the court of Adolf Fredrik, next in line for the Swedish crown, by 1743. He was the organist at St Klara, Stockholm (1745) and the queen's music teacher (1753). The appointment for court organist came in 1763 and by 1771 he had acceeded to the position of the musical director of the French-Theatre. Johnsen was an excellent countrapuntist and improvisation impresario. His fame was established, however, with his collection of delightful songs. ~ Keith Johnson, Rovi