He assumed the position on September 12, 2018 following the retirement of Vice Admiral James W. Crawford, III and relinquished it on August 18, 2021 to Darse Crandall.

[3][4] Hannink initially served as a Naval Aviator, assigned to Sea Control Squadron 33 (VS-33) at NAS North Island, flying the S-3 Viking and deploying aboard the aircraft carrier USS Nimitz (CVN 68).

Upon graduation from Baylor Law School in 1994, Hannink transferred from the unrestricted line to the Judge Advocate General Corps.

He has also served as the special assistant to the Secretary of the Navy, Deputy Legal Counsel to the Joint Chiefs of Staff, special counsel to the Chief of Naval Operations, and the Deputy Staff Judge Advocate for the United States Pacific Command.

[1] On 11 June 2018, Hannink was nominated for promotion to vice admiral and assignment as Judge Advocate General of the Navy.