In the early days, Dolan provided specialized programming to hotels through his Teleguide service, while cable TV gained popularity in rural regions.
In 1964, he struck a deal to install cable in Manhattan buildings and later secured the rights to air Knicks and Rangers playoffs on cable to attract viewers, as noted by Variety.
Dolan went on to establish Home Box Office (HBO) for movies and eventually sold his cable service and HBO to focus on building Cablevision, which delivered TV and internet services to homes in the northeastern U.S.
In 2015, the Dolan family sold Cablevision to the European company Altice for approximately $18 billion (£14.3 billion).
By then, Dolan’s son, James, was managing what The New York Times described as the family’s empire. However, the Dolans earned the reputation of being “the family New Yorkers often loved to hate,” due to frustration over the Knicks’ performance and disputes with networks that risked preventing customers from watching events like the Academy Awards and World Series.
At the time of his passing, Dolan’s net worth was estimated at $5.4 billion (£4.3 billion), according to Forbes.