Jay L. Kriegel, who as a 25-year-old prodigy helped shape the Lindsay administration’s progressive challenge to New York City’s entrenched power brokers, and who later emerged as one himself, in fields ranging from television broadcasting to real estate development, died on Thursday at his weekend home in South Kent, Conn. He was 79. The cause was complications of melanoma, his wife, Kathryn McAuliffe, said. A charter member of Mayor John V. Lindsay’s so-called kiddie corps, Mr. Kriegel played an outsize role as chief of staff and special counsel in an administration that held power from 1966 to 1973. Later, as an indefatigable but pragmatic outside process broker, he continued to influence a broad spectrum of policymaking through the same power of persuasion. In the late 1970s, Mr. Kriegel and Steven Brill founded The American Lawyer magazine, with Mr. Kriegel as its publisher. In 1986, facing a Reagan administration proposal to repeal state and local tax deductions on federal returns, Mr. Kriegel galvanized the New York opposition that helped scuttle it. As the senior vice president of CBS Inc. in the late 1980s and early ’90s — working under Laurence A. Tisch, its chief executive and largest stockholder at the time — Mr. Kriegel engineered a major, lucrative legislative victory for broadcasters over the cable television industry. He was later executive director of NYC2012, a long-shot campaign set up by Michael R. Bloomberg’s administration to woo the 2012 Summer Olympics to New York. The city derived some enduring benefits from the bid, including an extension of the Flushing subway, the commercial and residential development of Hudson Yards on Manhattan’s West Side and the building of Citi Field in Queens, home of the Mets, and the Barclays Center arena in Brooklyn, home of the Nets. Mr. Kriegel was also counselor to the financial communications firm Abernathy MacGregor Group; counseled the governments of Turkey and Kazakhstan; and most recently served as senior adviser to the Related Companies, the global developer that created Hudson Yards. Jay Lawrence Kriegel was born on Oct. 10, 1940, in Brooklyn to the children of Jewish immigrants from Eastern Europe, I. Stanley Kriegel, who headed an accounting firm, and Charlotte (Karish) Kriegel. After graduating from Midwood High School in Flatbush, he received a bachelor’s degree in English from Amherst College in 1962 and a law degree from Harvard. Early in 1965, Mr. Kriegel and several other Harvard Law students were recruited by Mr. Lindsay, then a Republican congressman, to draft sections of what became the Voting Rights Act of 1965. Afterward, instead of accepting a job with Judge Thurgood Marshall, the newly named solicitor general and future Supreme Court justice, Mr. Kriegel joined Mr. Lindsay’s 1965 mayoral campaign to conduct research. When Mr. Lindsay won the election, Mr. Kriegel was named assistant to the mayor for social welfare and law enforcement. As the mayor’s chief of staff, Mr. Kriegel was thrust into the limelight in the early 1970s after two whistle-blowing police officers, quoted by The New York Times, accused the administration of having failed to pursue their specific allegations of police corruption. The officers were later identified as Sgt. David Durk and Detective Frank Serpico. After Mr. Lindsay left office at the end of his second term in 1973, Mr. Kriegel was named director of special projects for the Loews Corporation, which Mr. Tisch owned with his brother, Preston Robert Tisch; he served in that capacity from 1975 to 1978. He was publisher of The American Lawyer from 1979 to 1982. At CBS, where he was senior vice president from 1988 to 1993, Mr. Kriegel helped persuade Congress to require the cable TV industry to pay broadcasters for the right to retransmit over-the-air programming. Mr. Kriegel later ran his own strategic consulting firm and served on numerous philanthropic and civic group boards, including Prep for Prep and New Visions for Public Schools. His marriage to Joanne Connors in 1971 ended in divorce. In addition to his wife, Ms. McAuliffe, an artist, he is survived by two children from his first marriage, Isabel Hardy and Connor Kriegel; his stepchildren, Jevon and Caitlin Roush and Tessa Bridge; his sister, Myra Zuckerbraun; four grandchildren; and three step-grandchildren. He lived in Manhattan.