Napoleon Ardell McCallum now wears the uniform of an ensign, and like he said between the anthems and applause, this one doesn't have numbers on the back.

McCallum graduated from the Naval Academy and was commissioned as an officer today in a small private ceremony in Memorial Hall, a large tradition-filled room flanked by framed sea battles and rolls of honor. He received his diploma and new dress blues before a crowd of about 150 family and friends in a brief, pleasant rite that bound him to the U.S. Navy for the next five years, precluding professional football for the time being.

"I like this uniform," McCallum said. "I feel good in it."

McCallum departs as the most accomplished running back in the history of the Naval Academy, with 26 school rushing and receiving marks, including the NCAA all-purpose yardage record. He also leaves as one of its most exceptional midshipmen. In an unprecedented decision, the Naval Academy allowed him to return for a fifth season under an NCAA medical hardship provision after breaking his ankle in 1984 and missing most of what would have been his senior season.

Foregoing graduation with his class last June, McCallum earned a second science degree and underwent today's ceremony with just one other midshipman, who was also departing under special circumstances. Bernard Mimms was commissioned a second lieutenant in the U.S. Marine Corps, to mark the end of a three-year battle with testicular cancer that threatened his military career. He underwent four operations and chemotherapy, lost 50 pounds and took his cause to the White House before he was declared fit and allowed to receive his degree and commission.

McCallum and Mimms sat side by side in the middle of the large room at the top of the staircase in Bancroft Hall, the barracks that houses the Brigade of Midshipmen. McCallum's parents, Napoleon and Virginia, and his 18-year-old sister Ovajuniste, from Milford, Ohio, sat behind them along with various midshipmen, Academy officials, about 20 members of the Navy football team, Coach Gary Tranquill and Athletic Director Bo Coppedge.

Before the conferring of degrees and taking of oaths they were addressed by Adm. Charles R. Larson, superintendent of the Naval Academy. Larson substituted for President Reagan, who usually makes the remarks to graduating midshipmen.

"Your path here may have been a little longer, the ceremony a little smaller and you've got me rather than the president," Larson said. "But that does not in any way diminish the importance of what you have done."

"You messed it up," Mimms told McCallum. "I could have had my own ceremony."

The pair descended the ornate marble staircase for a small hat-tossing rite in the lobby. McCallum had said in an interview earlier this year that he would regret missing the hat-tossing ceremony as part of graduation with his class, as well as the traditional handshake from Reagan. But McCallum said today he and his family got a private handshake from the president five weeks ago when they were invited to the White House.

"He said he had read what I said in a newspaper and thought it would be a nice idea," McCallum said.

McCallum was a revered midshipman, but he was once a reluctant one. He briefly contemplated leaving Navy his sophomore year to avoid the five-year service commitment and perhaps be able to play professional football. But he was persuaded to stay by his father, who wanted to see him become an officer.

"It's quite an accomplishment," the elder McCallum said today. "It's a once-in-a-lifetime opportunity."

McCallum will play in three postseason games -- the Senior Bowl, Hula Bowl and Blue-Gray -- then will return to Annapolis temporarily while he waits for an opening in supply corps school in Athens, Ga. Like the last Navy graduate to be drafted by the NFL, running back Eddie Meyers, McCallum will save his leave to attend training camp. Compared to the potential money he might have made immediately in pro football, his officer's salary will amount to much less.

"I don't worry about pro football," he said. "I can still make it if I want to, I think. Money is important, but there are other things, too, and this was worth it."

McCallum's fifth season was a personally successful one despite Navy's 4-7 record. He set the all-time NCAA career all-purpose yardage record with 7,172 yards, shattering Darrin Nelson's mark of 6,885 set at Stanford. McCallum rushed for 1,327 yards this season and finished seventh in the Heisman Trophy voting.

The climax of his career came Dec. 7, when he rushed for 217 yards in Navy's 17-7 upset victory over Army in Philadelphia, for which he was carried off the Veterans Stadium field by the Brigade of Midshipmen. "That moment was it," he said. "My greatest experience."

"I think that said a lot about how the Brigade feels about him," Coppedge said. "He's respected by everyone. He wears a uniform better than anybody; it always hangs just right on him."

Coppedge said that there is an excellent chance McCallum's jersey number, 30, will be retired sometime in the next three weeks. Only two other Navy athletes have been so honored: Heisman Trophy winners Roger Staubach and Joe Bellino.

The idea must be agreed on by the Navy Athletic Association Board of Control. "I probably could have gotten a yes vote in about 20 seconds after the Army game," Coppedge said. "I would think (it will be retired)."

Tranquill left immediately after the ceremony and went back to his office, with recruiting in full swing. Navy will have to change some of its offense without McCallum, who also set the NCAA record for all-purpose plays, with 1,337, breaking Tony Dorsett's mark of 1,120 set at Pittsburgh.

"You replace him, but you don't fill his shoes," Tranquill said.