The Diff'rent Strokes star, who suffered from a congenital kidney disease, was admitted to Utah Valley Regional Medical Center on Wednesday (26May10) following a fall at his home.
He was fully conscious after the accident but his condition gradually worsened. On Thursday (27May10) his manager, John Alcantar, revealed he was "unconscious and on life support".
Coleman's wife Shannon decided to take him off life support early on Friday (28May10) and he died at around 12.05pm (local time) from an intracranial haemorrhage.
A statement released by his rep reads: "Thanks to everyone for their well wishing and support during this tragic time. Now that Gary has passed, we know he will be missed because of all the love and support shown in the past couple of days.
"Gary is now at peace and his memory will be kept in the hearts of those who were entertained by him throughout the years."
Coleman, the adopted son of nurse Edmonia Sue and her partner W.G. Coleman, began his TV career in the early 1970s with small parts in The Jeffersons and Good Times before landing his breakthrough role as Arnold Jackson in Diff'rent Strokes in 1978.
He starred for eight years alongside his TV brother Todd Bridges, who played Willis Jackson, as two African-American boys adopted by wealthy Caucasian widower Phillip Drummond (Conrad Bain).
Coleman fast became the show's most popular star, known for his character's catchphrase, "What'choo talkin' 'bout Willis?" and eventually earned $100,000 (£66,670) per episode.
He went on to score his own animated series, The Gary Coleman Show, and voiced his character for a year before it was axed in 1983.
He later won guest roles in a variety of small screen projects, including a cameo as Jackson in a 1996 episode of Fresh Prince of Bel-Air, as well as appearances in TV sitcoms My Wife and Kids and Married... with Children, and a voiceover part in The Simpsons.
Coleman also starred in a number of made-for-TV movies including The Kid with the Broken Halo (1982), Playing with Fire (1985), Fox Hunt (1996) and 2003's A Christmas Carol.
His last film role was in 2009's Midgets vs. Mascots.
Despite his many TV and film appearances, Coleman struggled financially and he successfully sued his parents and former manager in 1989 for misappropriating his $3.8 million (£2.53 million) trust fund. In 1993, he was awarded $1.28 million (£853,340).
However, he filed for bankruptcy in 1999, citing the early mismanagement of his trust for his money problems.
Coleman was no stranger to the law and was arrested on a few occasions for assault and disorderly conduct.
His most recent arrest occurred in January (10) when he was suspected of domestic violence following an alleged altercation with his wife Shannon Price, who he wed in 2007. He was handed a fine in February (10) and ordered to attend domestic violence classes in exchange for avoiding jail.
The actor's career was also overshadowed by his many health problems, after undergoing two kidney transplants in 1973 and 1984, which required frequent dialysis. He had heart surgery last year (09) and spent the past few months in and out of hospital suffering from seizures, which saw him collapse during a round of telephone interviews in January (10).
Coleman was hospitalised again in February (10) after another apparent seizure while on the set of U.S. TV news programme The Insider.
He is survived by his wife Price, who he reunited with in April (10) after a few months' estrangement. The couple had no kids.