Lawrence D. Ackman, a Cityscape’s Financier, Dies at 83

Lawrence D. Ackman, a behind-the-scenes power in New York real estate who put together the financing for major projects that changed the city’s skyline, died on May 31 in Boston. He was 83.

His death, at Massachusetts General Hospital, was confirmed by his son, Bill, a prominent hedge fund manager.

In his nearly five decades at the Ackman-Ziff Real Estate Group, a firm founded by his father and an uncle under a different name, Mr. Ackman helped develop the mortgage brokerage industry — the business of helping developers borrow money to finance real estate projects. He was instrumental in putting together the land and financing for deals struck by some of New York’s leading developers.

In a talk at the Center for Jewish History in Manhattan in 2015, Mr. Ackman recounted how early in his real estate career, when he was 35, he pitched the developer Seymour Durst on how to use a piece of West Side property in Manhattan — the block from West 42nd to West 43rd Street between Ninth and 10th Avenues. Mr. Ackman proposed a high-rise apartment building with a tennis club and a health club, he said. That property, built in the 1970s, became the 46-story Manhattan Plaza complex, a federally subsidized apartment complex for artists.

Among Mr. Ackman’s many clients were the Friedland family, with its Friedland Properties development firm, which he represented on most of its acquisitions that reshaped Madison Avenue on the Upper East Side. He also helped arrange a $100 million construction loan for the developer Harry Helmsley to build One Penn Plaza, a 57-floor skyscraper on Seventh Avenue between 33rd and 34th Streets. The loan was, at the time, one of the largest ever made.

In the 1990s, Mr. Ackman helped the developer Irwin Cohen finance the acquisition of an old Nabisco factory complex on Ninth Avenue, between 15th and 16th Streets. Mr. Cohen turned the property into Chelsea Market, a food hall and retail complex that helped revitalize a desolate stretch of the neighborhood.

“Larry didn’t know anything except honesty,” Mr. Cohen said in an interview. “The people he introduced me to relied upon what he said. And when he said, ‘Irwin is good people,’ they trusted him, and it’s not a trait that you find in most people in the real estate business.”

Lawrence David Ackman was born in New York City on April 29, 1939, to Herman and Jean (Miller) Ackman. His mother died when he was 13, and his father later married Hazel Harte. He grew up in Manhattan and in the Bronx and attended Riverdale Country School.

Mr. Ackman graduated from Brown University, where he studied economics, and received an M.B.A. from Harvard Business School. He enlisted in the Army in 1960. He spent six months on active duty, teaching basic artillery mathematics at the Fort Sill Artillery Training School in Oklahoma, and five and a half years in the Army Reserve.

In 1963 he married Ronnie Posner, whom he first met at a Howard Johnson’s in Naples, Maine, when the two were camp counselors. (Ms. Ackman later became known as the family’s first activist investor, preceding their son, Bill, as she pushed for the electrification of the Metro-North Railroad.)

Mr. Ackman retired from Ackman-Ziff after nearly 50 years, but stayed on as chairman. In 2009, he took an office at his son’s investment firm, Pershing Square, and formed a real estate investment partnership with him. Together they acquired more than 3,000 apartment units in Philadelphia and New Jersey. In New York, they own, alongside William Friedland, the Apthorp Retail condominium, the ground retail space inside the landmark 12-story Apthrop condominium on Broadway between 78th and 79th streets. They also own, with partners, the historic Hotel Chelsea.

Mr. Ackman was an active philanthropist, inspired by his mentor, the real estate investor George Jaffin, a noted art patron. Among his endeavors, Mr. Ackman endowed an ethics program at Harvard Business School and funded a documentary series to teach business ethics, produced by the New York public television station WNET.

Mr. Ackman was on the board of the New York Philharmonic,for which his firm helped arrange, pro bono, the financing for the $550 million renovation of the music hall at Lincoln Center now called David Geffen Hall. He also funded the purchase of the hall’s new digital organ.

Outside work, he traveled to more than 70 countries with his wife and enjoyed performing songs with her for friends — her on the piano, him singing tunes from the American songbook in a rich baritone voice.

In addition to his son and his wife, he is survived by a daughter, Dr. Jeanne Ackman, and seven grandchildren.