Conrad Yeatis Clark spent his teens in Pittsburgh and moved to Los Angeles when his mother died. There he began making a name for himself on the LA club scene, and by the time he had joined Buddy DeFranco in 1953, his style was in place, a bluesy take on bebop which had strong links to the Horace Silver style. The sessions with DeFranco for Verve are full of understated mastery from both clarinettist and pianist. But Clark already had a heroin habit, and when he went to New York in 1957 (initially as Dinah Washington's pianist) his problems ran his life, even though he managed a prolific career in the recording studios. Alfred Lion of Blue Note especially liked him, and he appeared on 29 different dates for the label. Sonny Clark Trio (1957) is a small masterpiece, Clark essaying a version of Be-Bop where he rolls out chorus after chorus of impish, funky invention. A gracious accompanist, he was much liked by several horn players – Dexter Gordon in particular – and admired by fellow pianists, and even when live work became problematical because of both his habit and an increasing dependency on alcohol, he was still offered many record dates. His death was a melancholy finale: ostensibly from a heart attack, his demise was brought on by a drug overdose in the back of the club where he was working, and the owners shifted his body to a nearby apartment to avoid the resulting publicity.

Biography from Richard Cook's Jazz Encyclopedia (2005).

If you'd like more information, check out The New Grove Dictionary of Jazz (2002) or The Biographical Encyclopedia of Jazz (2007), both of which are still in print.