Count Basie (1904–1984) was one of the most influential figures in jazz history. His Kansas City-style big band became the definitive swing orchestra, featuring a loose, blues-based approach and a rhythm section that defined the era. Basie's orchestra was known for its relaxed swing feel, powerful brass section, and the legendary 'All American Rhythm Section.' Songs like 'One O'Clock Jump' and 'April in Paris' became jazz standards. His orchestra continued performing for decades, making him one of the longest-running bandleaders in jazz.