Koji Sekimizu was born on 3 December 1952 in Yokohama, Japan.  He graduated in 1975 with a Bachelor’s degree in engineering at the Engineering Faculty of Osaka University, and obtained a Master’s degree in engineering in 1977 at Osaka University.

In April 1977, he entered the Ministry of Transport of Japan (MOT) and was appointed as a Ship Inspector in the Nagasaki district branch of Kyushu District Maritime Bureau.

In April 1979, he moved to the headquarters of MOT and acted as the chief officer in charge of IMO regulations in the Safety Planning Section of the Ship Bureau and drafted various proposals to IMO’s technical sub-committees.

In July 1980, he was transferred, under a special arrangement, to the Shipbuilding Research Association of Japan to engage in his duties to attend committees and sub-committees of IMO. In 1992 he was promoted to and appointed as Head of the Technology Section. After this, he worked for the Maritime Safety Division until October 1997.

In October 1997, he was promoted to Senior Deputy Director of the Marine Environment Division, and was then appointed as Director of the Marine Environment Division in August 2000.

In his capacity as Director of the Marine Environment Division (MED), he led the Marine Environment Division in discharging its responsibilities to support the work of among other things the Marine Environment Protection Committee (MEPC) in dealing with the phase-out schedule of the single-hull tankers and the Condition Assessment Scheme proposed in the aftermath of the Erika (1999) and Prestige (2002) incidents and handling a number of emerging new environmental issues including harmful anti-fouling paints, ballast water management, ship recycling, particularly sensitive sea areas (PSSAs) and greenhouse gas emissions from ships.

In January 2004, he was appointed as Director of Maritime Safety Division and has contributed to the activities of IMO in preparation, adoption and implementation of international rules and regulations including the implementation of the International Ship and Port Facility Security (ISPS) Code, the development of the Long-Range Identification and Tracking of Ships (LRIT) system, etc.

He has made major contributions to the creation of the Cooperative Mechanism established by the three littoral States in the Straits of Malacca and Singapore; and the adoption of the Djibouti Code of Conduct.

On 28 June 2011, he was elected Secretary-General by the 106th session of the Council and, having been approved by the 27th session of Assembly, appointed, on 1st December 2011, the seventh Secretary-General of IMO by the 107th session of Council for the period from 1 January 2012 to 31 December 2015.

Mr. Koji Sekimizu received the Doctor Honoris Causa honorary title of Nikola Y. Vaptsarov Naval Academy on 14.10.2015.