they called him the admiral! but david robinson only earned the rank of a LIEUTENANT junior grade (LT JG)

CLASS OF 1987 - DAVID ROBINSON

Upon graduating from Annapolis in 1976, I (Jordan B. Smith, Jr.) received a Regular Commission and a six year obligation to serve in the Marine Corps. But other sports players served shorter terms and most people do not know or understand how this can happen.  For instance, Roger Staubach served his six year term and so did Phil McConkey before entering the NFL.  Robinson was 6 ft. 8 in. when he was admitted to the Naval Academy, two inches above the height limit, but received a waiver from the Superintendent of the Academy. Robinson considered leaving the academy after his second year, before incurring an obligation to serve in active duty. He decided to stay after discussing with the Superintendent the likelihood that his height would prevent serving at sea as an unrestricted line officer, hurting his naval career, and might make it impossible for him to be commissioned at all.

The height restrictions are because of the height of the ceilings on most Naval Ships. By the time he took the court in his first basketball game for the Navy Midshipmen men's basketball team, he had grown to 6 ft 9 in (2.06 m), and over the course of his college basketball career he grew to 7 ft 0 in.

As a compromise, Secretary of the Navy John Lehman allowed Robinson to train for and receive his commission as a staff officer in the Civil Engineer Corps community. As a result, Robinson was commissioned in the Naval Reserves and had to serve only an initial active-duty obligation for two years. After graduating from the Naval Academy, Robinson became a civil engineering officer at the Naval Submarine Base Kings Bay in Georgia. He was regularly featured in recruiting materials for the service. Despite the nickname "Admiral", Robinson's actual rank upon fulfilling his service commitment was Lieutenant, Junior Grade.
He began college with no expectations of playing in the NBA, but in Robinson's final two years he was a consensus All-American and won college basketball's two most prestigious player awards, the Naismith and Wooden Awards, as a Naval Academy first class man (senior).

In 1986, Robinson led Navy, a number seven seed, within a game of the Final Four before falling to Duke in the East Regional Final. Robinson played his first three years for the Midshipmen under Paul Evans (who left Navy to coach at Pitt) and his senior season under former University of Georgia interim Head Coach Pete Herrmann. Upon graduation, he became eligible for the 1987 NBA draft and was selected by the San Antonio Spurs with the first overall pick; however, the Spurs had to wait two years because he had to fulfill his active-duty obligation with the Navy.

Reference
Wikipedia, Nimitz Library, USNA