Subsequently, Dolan expanded his influence by building Cablevision, which transformed telecommunications in the northeastern United States. In 2015, Cablevision was sold to European firm Altice for nearly $18 billion, with Dolan's son, James, at the helm of the family business. Despite their wealth, the Dolans often found themselves at odds with the public over issues related to the New York Knicks and their broadcasting disputes, which led to widespread frustration among fans.

At the time of his death, Dolan's net worth was estimated at $5.4 billion, reflecting his profound impact on the entertainment industry.