Mario Buatta, the acclaimed New York interior designer known as “the Prince of Chintz,” whose cozy, clubby rooms defined the Americanized version of the English country look, died Oct. 15 at a hospital in Manhattan. He was 82.

The cause was pneumonia, said his brother and sole immediate survivor, Joseph Buatta.

Few interior designers become famous. Mr. Buatta did. His career spanned more than five decades, in which he made every top-designers list and earned every award in his field while swagging and swatching his way through America’s living rooms with comfy club chairs, dog portraits, blue-and-white porcelains, glazed walls, tassels and floral chintz fabrics — preferably slightly faded.

Mr. Buatta became widely known for his signature style in the 1980s while working with wealthy clients who had tired of the cold look of modern furniture and wanted an “old money” look. His romantic and colorful window treatments, old furniture and tasseled pillows evoked privilege but soon trickled down to the masses as the English country style became the favored look in decorating magazines and in homes from Birmingham to Boston.

“People who have made money want to look like people who have inherited money,” Mr. Buatta said in 1986 in the magazine Manhattan, inc., when the publication featured him on its cover in a blue-and-pink chintz suit. “They treat decorating as fashion.”

In the decorating community, Mr. Buatta was a giant with a sometimes outrageous sense of humor, and a staple at society dinners and benefits such as the prestigious Kips Bay Decorator Show House, where he sometimes pulled a scraggly toupee out of his pocket and wore it for laughs.

“He was just a mix master at taking two different fabrics and putting them together like nobody else could. You think of these in­cred­ibly beautiful florals and how cheery and happy they look,” said Alex Papachristidis, a New York designer. “What he did looked collected, but it was actually just decorated.”

Notable deaths in 2018 and 2019: Nipsey Hussle, George H.W. Bush, Stan Lee, John McCain, Aretha Franklin and other famous faces we’ve lost

Nipsey Hussle, a Grammy nominated rapper who sought to revive South Los Angeles, died at age 33 on March 31. Read the obituary (Matt Winkelmeyer/Getty Images for Warner Music)

Mr. Buatta pretty much ran his firm himself (he was notorious for firing assistants), juggling clients such as Mariah Carey, Wilbur and Hilary Ross, Barbara Walters, Billy Joel, Malcolm Forbes and Henry Ford II. He loved publicity and cashed in on his celebrity decorator status, becoming one of the first interior designers to sign lucrative licensing contracts for lamps, furniture, sheets and fabrics bearing his name. He even designed a line of potpourri for Aromatique.

“You either love it or you hate it,” Mr. Buatta said of his honeysuckle fragrance. “It permeates the house and lasts forever. But that’s good. People don’t want to throw their money away.”

The scent even wafted through the fancy drawing rooms of Blair House, the official president’s guesthouse for visiting dignitaries, which Mr. Buatta redid in the 1980s with Mark Hampton. Each designer decorated about 50 rooms with English and American antique furniture, fine artworks, old silver, grand mirrors, floral wallpaper and Chinese export porcelain.

“The place looks like the beautiful home of someone who lives in a historic house with lots of family pieces,” Mr. Buatta told The Washington Post in 2009. “They wanted it to look like a house, not a hotel.”

Mario Buatta was born on New York’s Staten Island on Oct. 20, 1935. His father, Felix, was a violinist and band leader who worked under the name Phil Burton and once played with Rudy Vallee and the Connecticut Yankees; his mother, Olive, was a homemaker who always let him rearrange the furniture.

When he was 16, he painted his bedroom chocolate brown and his closet red. Mr. Buatta thought that he wanted to be an actor, but in 1959 he ended up with a job at B. Altman & Co., a waspy Manhattan department store, as an assistant in the decorating department.

Mr. Buatta took courses in architecture and decorative arts, including a European summer session sponsored by the Parsons School of Design. While abroad, he fell in love with English country houses and the work of John Fowler and Nancy Lancaster, who layered furniture, fabrics and accessories with a sense of history.

He worked for designer Elisabeth Draper and later Keith Irvine before opening his own firm in New York in 1963.

Mr. Buatta lived in an overflowing apartment on the Upper East Side with his beloved dog paintings (which he called his ancestral portraits), slipcovered sofas and endless accessories, including lacquered boxes, porcelain cabbages and needlepoint pillows. He liked to tell guests that dust was a protective coating for fine furniture.

He had a proclivity for bad puns and would buy gag gifts by the case, things like fart machines and hair nets covered in pink curlers. Sometimes he started his lectures speaking in a heavy Italian accent.

In 2013, Rizzoli published Mr. Buatta’s first and last book, “Mario Buatta: Fifty Years of American Interior Decoration.” It weighed seven pounds, and Mr. Buatta referred to it as the “Buattapedia.”

“The Mario Buatta look has come to define an era in American culture as ebullient and luxuriant as the beauty of his rooms,” wrote his co-author, design historian Emily Evans Eerdmans. “The pendulum of fashion swings back and forth,” she added, “but Mario has always been secure knowing that beauty and comfort never go out of style.”

As news of his death broke Monday evening, the design community flooded Instagram with chintz-filled photos and tributes. “Thank you for making the world a more colorful place, dear Mario Buatta. You certainly inspired us . . . and thank you, Harold,” wrote John Loecke and Jason Oliver Nixon, of the North Carolina design firm Madcap Cottage.

Harold was the name of Mr. Buatta’s pet plastic cockroach, which accompanied him to parties.