Nara Chandra Babu Naidu served as Chief Minister of Andhra Pradesh for the longest duration - from 1995-2004 (9 years) and again from 2014-2019, totaling approximately 9 years and 9 months. Y.S. Rajasekhara Reddy served from 2004-2009 (5 years), N.T. Rama Rao had two separate terms totaling less than 7 years, and Kasu Brahmananda Reddy served from 1964-1971 (7 years).