He spent virtually his entire life in Hawaii, with the exception of a number of collecting expeditions, primarily to islands in the Pacific Ocean (including the Mangarevan Expedition in 1934), and his time spent at Harvard University, where he received a Doctor of Philosophy under the direction of William J. Clench in 1955. He was known to most people as "Yoshi". Kondo spent his entire career, over 40 years, at the Bernice P. Bishop Museum in Honolulu.
During most of that period, his official position was "Curator of Mollusks".
His main research interests involved land snails in the families Achatinellidae and Partulidae, groups for which he was a major authority, although he did work with other mollusks as well.