Sergio Pininfarina, whose Italian engineering design firm conceived the sensuous bodies that made Ferraris look fast at a standstill and whose futuristic car designs were decades ahead of their time, died July 3 at his home in Turin. He was 85.

His death was announced by Pininfarina, the design company his father started in 1930. The cause was not disclosed.

In the automotive world, the names Pininfarina and Ferrari evoke speed, style and splendor. Their names were inextricably linked beginning in the early 1950s when Battista “Pinin” Farina began a business relationship with Enzo Ferrari, owner of the renowned Italian sports car manufacturer.

Sergio Pininfarina became chairman after his father’s death in 1966 and helped transform the small custom shop into a worldwide design empire.

During the 1950s, the company produced under 1,000 cars a year for mainly Italian auto companies. Mr. Pininfarina helped expand the design firm’s operations, reaching a peak annual production of nearly 50,000 units for clients including Peugeot, Rolls Royce, Maserati and Cadillac.

As chairman, Mr. Pininfarina had the final word on all aspects of a car’s look. “Good design equals longevity, and the better the design, the longer its life,” Mr. Pininfarina once said. “A beautiful car — like a beautiful woman — is always beautiful.”

Ferrari Chairman Luca di Montezemolo said the two companies flourished under Mr. Pininfarina’s stewardship. “Calling his relation with Ferrari legendary is insufficient,” Montezemolo said in a statement, noting that Mr. Pininfarina was known for his “sense of elegance.”

For Ferrari, Mr. Pininfarina oversaw the body design of the 1968 Daytona, known for its long, sloping hood; the 1984 Testarossa and its dramatically vented doors; and the 1987 F40, with its signature rear wing. His last contribution was the 2002 Enzo supercar, inspired by the low-slung bodies of Ferrari’s champion Formula 1 cars.

Rich Selikoff, the development director at the Saratoga Automobile Museum in Upstate New York, said Mr. Pininfarina’s designs had a timeless quality.

“He was truly a trendsetter on all levels,” Selikoff said in an interview. “He was setting the bar and the standard for the future. His designs were always 10 or 15 years ahead of their time. Sometimes more. He’d conceptualize the trend before it ever existed.”

Selikoff said that in the 1950s and 1960s, when other designers made cars that were “land yachts” with fins, Mr. Pininfarina produced aerodynamically sleek roadsters that became the rage a decade later. His 1965 Dino Berlinetta Speciale, a prototype with swooping front fenders, greatly influenced future generations of Ferraris.

Sergio Farina was born Sept. 8, 1926, in Turin. He studied mechanical engineering at Turin Polytechnic and then joined his father in business. The family’s last name became Pininfarina by presidential decree in 1961.

Mr. Pininfarina, with his bespoke suits and wire-framed glasses, became a well-known cultural figure in Italy. He served in the European Parliament from 1979 to 1988. In 2005, he was made a senator for life in Italy, an honor reserved for select members of society.

Survivors include his wife, Giorgia; a son, Paolo; and a daughter, Lorenza.

His son Andrea, who took over the family business when Mr. Pininfarina stepped down in 2006, was killed in 2008 when his Vespa was struck by a car.

After Andrea’s death, Paolo became the leader of the company, which suffered financially in the 2000s.

Sergio Pininfarina remained synonymous with the company’s heyday. “If you think of painting, if you think of sculpture, if you think of architecture, Italian people have always been famous for arts,” he told the New York Times in 1987.

He said that his luxury as a car designer was that his business catered to an elite clientele, compared with larger American auto companies that designed for mass appeal.

“You make a new car and you invite a dozen people, a dentist, a sportsman, a lawyer, a prostitute. And you say, do you like this, do you prefer that? I accept it, but I am not an enthusiast, and I’ll tell you why,” Mr. Pininfarina told the Times. “I am looking to the future, and these people are accustomed to the past.”