George Mikan, the “gentle giant” who a half-century ago brought fame and stability to the fledgling world of professional basketball and literally transformed the game, died Wednesday at a Scottsdale, Ariz., rehabilitation center after a long fight with diabetes and kidney ailments. He was 18 days shy of his 81st birthday.

A superstar decades before the term existed, Mikan was the first big man to dominate the sport. No one before had seen a 6-foot-10 player with his agility, competitiveness, and skill.

When the Minneapolis Lakers came to New York in December 1949, the marquee at Madison Square Garden read “Geo. Mikan vs. the Knicks.”

“He literally carried the league,” Boston Celtics great Bob Cousy said. “He gave us recognition and acceptance when we were at the bottom of the totem pole in professional sports. He transcended the game. People came to see him as much as they came to see the game.”

College basketball instituted the goaltending rule because of him, and the NBA doubled the width of the free-throw lane. Slowdown tactics used against him – his 1950 Lakers lost 19-18 to the Fort Wayne Pistons in the lowest-scoring game in NBA history – eventually led to the 24-second shot clock.

Mikan led the Minneapolis Lakers to five league titles in the first six years of the franchise’s history. Nearsighted with thick glasses, he was as rough on the court as he was mild-mannered off it. Mikan led the league in personal fouls three times and had 10 broken bones during his playing career. He averaged 23.1 points in seven seasons with Minneapolis before retiring because of injuries in 1956. Mikan was the league’s MVP in the 1948-49 season, when he averaged 28.3 points in leading the Lakers to the title.

“Ed McCauley was our center. Eddie was 6-9, but weighed about 185 pounds, where George was probably 250,” Mr. Cousy recalled. “When we’d walk down the street in a group, Eddie would brush against a pole or big tree and say ‘Excuse me, George.’ Even to someone close to his height, George seemed humongous.”

A statue of Mikan taking his trademark hook shot was dedicated at the Target Center in Minneapolis in April 2001 at halftime of a Timberwolves-Lakers game.

“We were in hiatus a long time, the old-timers,” Mikan said at the time. “They forgot about us. They don’t go back to our NBA days.”

Timberwolves star and 2004 MVP Kevin Garnett knew of Mikan though.

“When I think about George Mikan, I skip all the Wilt Chamberlains and Kareem Abdul-Jabbars and I call him the ‘The Original Big Man,”‘ Mr. Garnett said. “Without George Mikan, there would be no up-and-unders, no jump hooks, and there would be no label of the big man.”

The Lakers moved to Los Angeles in 1960 and became one of the most successful franchises in professional sports.

Born June 18, 1924, in Joliet, Ill., Mikan didn’t play high school basketball, but when he entered DePaul, Ray Meyer, Mikan’s young new coach at DePaul, recognized the potential.

Mr. Meyer said he worked with Mikan alone for six weeks, making him shoot left-handed and right-handed, a procedure still known as the “George Mikan drill.”

He had him punch a speed bag, take some dancing lessons to improve his grace, and also jump rope.

Mikan was two-time college player of the year and led DePaul to the 1945 National Invitation Tournament title. He scored 53 points in the semifinals against Rhode Island, a phenomenal number in that era, and was named the tourney’s MVP.

Mikan played one season with the Chicago Gears before moving to the new Lakers franchise.

Mikan coached the Lakers for part of the 1957-58 season and was commissioner of the American Basketball Association in 1967, introducing the 3-point line and the distinctive red, white, and blue ball.

He practiced law and, in his later years, began pressing the NBA and the players’ union to boost the tiny pensions given to those who played in the league before 1965. His son, Terry Mikan, said most of his father’s awards and memorabilia has been sold. Mikan received a monthly pension check of $1,700, his son said. Under current rules, his widow will get half that much.

Terry Mikan said one of his father’s reasons for fighting so hard against his illnesses “was his hope that he would be alive when the collective bargaining agreement was reached and the decision had been finalized on the pre-65ers and their surviving families. He gave his heart and soul to that effort.”