At the time, he was selling private programming to hotels through the Teleguide service, while cable television was taking off in rural areas.
In 1964, Dolan struck a deal with New York to connect some Manhattan buildings to cable, and a few years later, hoping to attract viewers, he struck a deal to show the Knicks and Rangers playoff games on cable, according to Variety.
He then went on to create Home Box Office for movies, then sold both his cable service and HBO to build Cablevision, which ended up providing television and Internet to households throughout the Northeastern United States.
In 2015, the Dolan family sold Cablevision to European company Altice for approximately $18bn (£14.3bn).
By then, Dolan's son, James, was running what The New York Times called a family empire.
The Dolan family became “the family New Yorkers often love to hate,” according to The New York Times, frustrated with the Knicks' performance and fighting with networks over their programming that threatened to block customers from watching the Oscars and World Series.
Dolan was worth $5.4bn (£4.3bn) at the time of his death, according to Forbes.
