Among his most famous subjects was Queen Elizabeth II, who posed for Freud fully clothed after extensive negotiations between the palace and the painter. The colorful portrait, which the artist donated to the queen's collection, remains one of the most unusual and controversial depictions of the British monarch.
"It makes her look like one of the royal corgis who has suffered a stroke," said Robin Simon, editor of the British Art Journal.
Other critics said more enthusiastically that the work had broken the staid mold of royal portraiture.
In his studio, Freud worked extremely slowly and deliberately. People who posed for Freud said it sometimes took him months or years to complete a portrait because of his attention to every tiny detail and the complex nature of his brushwork, which gave his paintings a lifelike intensity.
He sometimes spent entire days mixing paints without putting a brush to canvas. When he did finally paint, he would wipe his brush on a cloth rag after every stroke. Great piles of rags lay on the floor of his studio and eventually he began to incorporate the rags into some of his paintings.
Freud often painted his friends, relatives and fellow artists. Others were simply ordinary people who received a small daily fee for posing for Freud. He usually refrained from using professional models because he felt they brought artifice into his studio.
His 1950-51 portrait of his first wife was to remain one of his most famous and best loved works. The detail of her features, the shadows in the room and her partial nudity are typical of the nuance and frankness of much of Freud's work.
Nudity became a central feature of Freud's art. Painting people without their clothes, he believed, peeled away their outer layer and helped reveal their instincts and desires.
"I'm really interested in people as animals," he told curators at the Tate Britain museum in advance of a major show in 2002. "Part of my liking to work from them naked is for that reason, because I can see more ... I like people to look as natural and as physically at ease as animals."
His first solo exhibition was at the Lefevre Gallery in 1944 after a brief stint working on a merchant ship during World War II. After the war, Freud left London for several years to paint primarily in France and Greece.
On his return in 1948, he started showing his work regularly at various exhibits and taught art at several schools.
His first major retrospective exhibition appeared at London's Hayward Gallery in 1974 to critical acclaim. Further retrospectives appeared in Paris, Berlin and Washington between 1987-88 and in 2002 at London's Tate Britain museum.
Freud's work can be found in major public collections around the world, including the Tate Gallery and the National Portrait Gallery in London, the National Gallery of Modern Art in Paris and the Museum of Modern Art in New York.
In 1998, prominent art critic Robert Hughes described Freud as "the greatest living realist painter."
Despite the accolades, he kept trying to improve his work even as the end of his life neared.
"I think the most dangerous thing for an artist would be to be pleased with one's work simply because it is one's own," he once said. "One wants every picture to be better than its predecessors. Otherwise, what's the point?"
The painter feuded for many years with his late brother Clement Freud, a popular writer and broadcaster who died in April 2009. He did not attend Clement Freud's funeral.
Freud's marriage to Kathleen Garman lasted four years and was dissolved in 1952. They had two daughters together. His second marriage, to Caroline Blackwood in 1953, ended in 1957.
Prentice, the spokeswoman, said in an email that funeral arrangements had not yet been made public.