Mr. Oku began his banking career in 1968 at The Sumitomo Bank, Limited. In 2003, he became Deputy President of SMBC, heading Corporate Banking and International Banking Units. In 2005, he was appointed President and CEO of SMBC and Chairman of the Board of SMFG, a holding company. During his tenure as President and CEO, he also served as Chairman of Japanese Bankers Association in 2007 and 2010. In April 2011, he resigned as President and CEO of SMBC to devote himself to his duties as Chairman of the Board of SMFG. He has been Vice Chairman of Nippon Keidanren (Japan Business Federation) since May 2011 and recently became a member of the Board of the Institute of International Finance, Inc.

Mr. Oku received his Bachelor of Law degree from Kyoto University in 1968 and his Master of Laws (LL.M) degree from Michigan Law School in 1975. He was awarded the Order of Industrial Service Merit Silver Tower from the Government of the Republic of Korea in 2009.