In the early 1960s, Dolan established Teleguide Inc., which provided information services via cable to New York City hotels. That same decade, he founded Sterling Manhattan Cable, the first urban cable television company in the nation. In its early years, Sterling forged first-of-its-kind agreements to bring New York professional Sports teams, cultural programming and movies into the homes of New York City cable viewers.
In the early 1970s, Dolan founded Home Box Office, the first premium programming Service in the cable television industry, which he sold to Time Life. Later he organized Cablevision Systems Corporation on Long Island and has spearheaded many of the company's advancements. Most recently, he was the vision behind VOOM, Cablevision's effort to expand content delivery and meet the demands of the exploding HDTV market, which was expected to include 6 million households by the end of 2003—and 12 million by year-end 2005.
From 2001 through early 2002, Dolan was a major bidder in the sale of the Boston Red Sox. He submitted a maximum bid of $750 million, but ultimately lost out to a group headed by John Henry, Tom Werner, and Larry Lucchino.
The Dolan Center for Science and Technology is John Carroll University's showcase building. Completed in 2003 at a cost of over $66 million, it houses JCU's science departments, including Mathematics and Computer Science.