Williams, whose major league baseball career was spent entirely with the Boston Red Sox, suffered an apparent heart attack and was pronounced dead on arrival at Citrus County Memorial Hospital in Crystal River on Florida's Gulf Coast.
Williams' health deteriorated in the 1990s and he was hospitalized with congestive heart failure in the fall of 2000. He had a pacemaker implanted after doctors discovered an increased heart rate.
On Jan. 15, 2001, he underwent a 9-hour open-heart operation to replace one valve and repair another. The procedure was unusually long because of excessive bleeding caused by medicine Williams had been taking.
As he prepared for the surgery, Williams said, "I've had a wonderful life. Let's go for it."
He was back in the hospital earlier this year, suffering from cardiovascular deterioration.
The ill health was a change form the way many remember Williams, a lanky leftfielder with the sweet swing who batted .344 and hit 521 home runs during a 19-year career.
"With the death of Ted Williams, America has lost a baseball legend," President Bush said in a statement. Bush, a former part-owner of Texas Rangers, said that Williams "gave baseball some of its best seasons, and he gave his own best seasons to his country. He will be greatly missed."
Baseball Commissioner Allan (Bud) Selig described Williams as one of baseball's all-time greats and a genuine war hero.
"I will miss him terribly," said Selig. "He was one of my heroes when I was growing up in Milwaukee and he had become my very good friend over the last decade. My condolences go out of his family."
Selig said Williams will be remembers Tuesday at the All-Star Game in Milwaukee.
Despite interruptions by two wars in his prime, the man they called "the Splendid Splinter" was a six-time American League batting champion, twice won the Triple Crown of batting -- for best average, most home runs and most runs batted in during the same season -- earned most valuable player honors twice (and came within a hair of winning a third), appeared in 18 All-Star games and was elected to baseball's Hall Of Fame in 1966, his first year of eligibility.
"This is a very sad day for baseball," former Red Sox third baseman Wade Boggs said. "One of the game's great legends is gone. Ted Williams was the John Wayne of baseball. A fighter pilot, a sportsman, an American hero."
A 6-foot-4, 200-pounder with keen vision, quick wrists and a scientific approach to hitting, Williams broke into the majors in 1939, a sensation from the start, and went on to a grand career despite missing nearly five seasons because of a several serious injuries and his two wartime excursions, as a Navy flier in World War II and, after being recalled, a Marine pilot in Korea, where he flew with John Glenn.
He was always fiercely independent and often sparred with the media and the Red Sox fans.
He had little interest in diversions, disliking smoking, drinking and parties (He told one interviewer he didn't like standing around "listening to a lot of bull----.").
Williams was an avid fisherman.
"This is a sad day for baseball, a sad day for anyone who knew Ted," New York Yankees Hall of Famer Yogi Berra said. "Nobody was more loyal, generous, courageous, more respected than Ted. He sacrificed his life and his career for his country. But he became what he always wanted to be -- the greatest hitter ever."
Williams was often mentioned as the best hitter in the history of major league baseball and he worked hard at it; with him it was an art. He was a different kind of batter -- he had been swinging a bat since he was a kid. As a child he would go into the yard at night after everyone else had retired, and swing away at an imaginary ball.
Even after turning pro, his Red Sox road trip roomies would often be awakened by him swinging a bat, a newspaper or anything he could find and accidentally knocking over something. He took great care of his bats, making sure they weighed 32-33 ounces, and even took them to a post office at times to weigh them.
And while he raged with the media (he had been known to spit and make obscene gestures toward the press box), he was cool at the plate. He followed the advice given early in his career by fellow Hall of Famer Rogers Hornsby, who had hit .424 in 1924. Hornsby told him simply, "Be patient, wait for your pitch."
"I am truly heartbroken," New York Yankees Hall of Famer Phil Rizzuto said. "We have lost another great ballplayer, another great person. Ted Williams was one of the most exciting players I ever saw."
Williams retired in 1960, appropriately right after hitting a home run in his last at bat, and dropped out of the public eye to devote more time to his fishing and enjoying hard-to-come-by privacy. But he was lured back to the game eight years later to manage the Washington Senators.
At first, he had success teaching his young club, winning the Manager of the Year award, but soon became discouraged because his players couldn't live up his standards and he quit after three years, after the Senators had moved to Texas and become the Rangers.
The public saw little of him after that. An expert angler, he made occasional appearances on TV fishing programs. In 1993 he was given a National Sports Award by President Bill Clinton. In 1999, he was named to the Major League All-Century team and, appearing before the All-Star game with some of baseball's legendary talent, the "splinter" stole the show by tipping his cap to the crowd, something he wouldn't do during his career.
A native of San Diego, Theodore Samuel Williams was born Aug. 30, 1918 the son of a Spanish-American war veteran who dabbled in photography and politics.
Ted's father, Sam, had trouble providing for his family and his mother, May, devoted most of her time to work for the Salvation Army.
He started his baseball career with San Diego of the Pacific Coast League in 1936. Purchased by the Red Sox in 1937, he hit .366 the following year with 43 homers and 142 runs batted in for their Minneapolis farm club in the American Association.
Called up by the Red Sox in 1939, Williams was an immediate star, batting .327 and leading the American League with 145 RBI in his rookie season. He raised his average to .344 in 1940 and then followed with his resplendent .406 in 1941. He was the first major leaguer since 1930 to achieve that feat. And, over the half century that followed, no one reached the .400 plateau for a season.
On the final day of the 1941 season, Williams was batting .399995, which would have rounded off to an even .400 and Boston manager Joe Cronin offered to let him sit out a twin bill with the Philadelphia Athletics. Williams refused, went 6-for-8 in the doubleheader and finished the season at .406.
Despite his magnificent feat, Williams failed to win the league's Most Valuable Player award that year. He finished second to Joe DiMaggio, who had batted safely in 56 consecutive games for the New York Yankees during the middle portion of the season. Williams won MVP Awards in 1946 and 1949 but shrugged them off with the comment, "MVP Awards are something people give you; batting titles are things you win yourself."
Williams won a second straight batting title with a .356 average in 1942 and then joined the Navy for World War II and missed the next three baseball seasons.
He returned in 1946 to lead the Red Sox to a pennant with a .342-38-123 offensive performance and win his first MVP award. But, he hit .200 in a disappointing World Series that the Red Sox lost to the St. Louis Cardinals in seven games. He won his third and fourth batting titles with .343 and .369 marks, respectively, in 1948 and 1949.
He suffered a fractured left elbow when he crashed into the left field wall making a catch in the 1950 All-Star game and finished that season with a .317 average in 89 games.
He was recalled to active duty in the Korean conflict at the age of 33 in 1952 and played a total of 43 games in the 1952-53 seasons. While in the service, Williams narrowly escaped death when he belly-flopped a flaming jet along 2,000 feet of runway in Korea. He returned from that war with an ear impairment that bothered him for the rest of his life.
Back with the Red Sox in 1954, he hit .345, .356 and .345 in successive seasons before winning his fifth and sixth batting titles with a .388 mark in 1957 and a .328 mark in 1958.
His 1958 performance at the age of 40 made him the oldest player to win a batting championship.
Williams hurt his neck on a fishing expedition following the 1958 season and batted .254 in 103 games in 1959, but he came back the following year, his last, and hit .316.
Williams was married three times, to Doris Soule, Lee Howard and Delores Wettach, all ending in divorce, and had two daughters, Bobby Joe and Claudia and one son, John.