Under the influence of his older brother, clarinetist Rolf Kühn, he began to get ever-more enthusiastic about jazz. After the first successes in the DDR, he moved in 1966 to West Germany and performed in the same year with his brother Rolf as well as at the Newport Jazz Festival and Berlin Jazz Days. In 1968 Joachim Kühn moved to Paris. Like groups in the free jazz idiom, he concentrated during the 1970s on projects in the jazz-rock area. In the mid-1970s he lived for a while in California. He achieved his greatest prestige as jazz piano virtuoso in the trio existing many years with bassist Jean-François Jenny-Clark and drummer Daniel Humair. He is among the few pianists with whom Ornette Coleman has played in concert. Joachim Kühn has performed in concerts extremely successfully during the last 40 years, completed tours with Bechstein grand pianos during the 1980s and recorded CDs on Bechstein. In 2006 one could read about one of Joachim Kühn's concerts: „Joachim Kühn wallows in furious runs with occasional aggressively expelled motives of the theme. Then he cushions the bass strings with the right hand in the voluminous sounding Bechstein grand piano and pounds a few chords with the left hand." A successful and long-lasting relationship.