HBO, Inc.'s origins trace to December 1, 1965, when Charles Dolan—who had already done pioneering work in the commercial use of cables—was granted a franchise permit by the New York City Council to build a cable television system encompassing the Lower Manhattan section of New York City (traversing southward from 79th Street on the Upper East Side to 86th Street on the Upper West Side).

Sterling's use of underground cables complied with a longstanding New York City Council ordinance—originally implemented to prevent broad-scale telephone and telegraph outages, after a severe blizzard affecting the Northeastern United States in March 1888 had caused widespread damage to above-ground utility lines in the area—requiring all electrical and telecommunication wiring to be laid underground to limit weather-related service disruptions, and because the multitude of tall buildings on Manhattan Island subjected television signals to reception impairments.

The proposed service would offer unedited theatrical movies licensed from the major Hollywood film studios and live sporting events, all presented without interruptions by advertising and sold for a flat monthly fee to prospective subscribers.

Dolan later presented his idea to management at Time-Life, who, despite the potential benefit to the company's cable assets, were initially hesitant to consider the "Green Channel" proposal.

[11][13][19] The namesake Home Box Office (HBO) pay television network was founded by Dolan—as a joint venture between Sterling Communications and its co-partner, Time Life Broadcasting Inc.—in 1972.

Sterling also raised Time's equity in the company to 66.4% in exchange for the added HBO stake, through the purchase of additional stock and a converted $6.4-million note obligation.

Gerald M. Levin—an entertainment industry attorney previously with New York City-based law firm Simpson Thacher & Bartlett, who had been with Home Box Office since it began operations as its director of finance, and later as its vice president and director of programming—replaced Dolan as the company's president and CEO; by September, he was joined by Time Life vice president J. Richard Munro as chairman of Home Box Office as well as Time-Life Broadcast's other subsidiaries, Manhattan Cable Television and NBC affiliate WOTV (now WOOD-TV) in Grand Rapids, Michigan (which became the company's lone conventional broadcasting property, after Time sold its other broadcast television properties as it began expanding into cable system ownership).

[8][35][36] On July 19, 1973, Time Inc. reached an agreement to purchase and assume financial liabilities of Sterling Communications for $6.2 million (including $3.1‐million in redeemed public debentures).

HBO also signed a $7.5-million agreement (including $6.5 million allocated by Levin) with RCA Americom to lease a transponder on the then-under construction Satcom I, which was expected to be launched at the end of 1975, for a five-year term.

[42][43][44][45][40] HBO began continuously transmitting via satellite on September 30, 1975, for the broadcast of the "Thrilla in Manila" heavyweight championship boxing match between Muhammad Ali and Joe Frazier from the Araneta Coliseum in Cubao, Philippines.

[25][48] In May 1976, Gerald Levin was promoted to chairman and CEO of Home Box Office Inc., succeeded as company president by Manhattan Cable president Nicholas "N.J." Nicholas Jr.[49] The ability of Home Box Office and other pay television services to offer a wide array of content was challenged on March 20, 1975, when the Federal Communications Commission (FCC) updated its pay-cable regulations to modify anti-siphoning regulations that further limited the operations of HBO and other movie- and sports-based cable services (including local and regional subscription television operations).

Home Box Office's first attempt at a secondary service was Take 2, a movie channel marketed at a family audience that launched in April 1979.

[62] HBO executives then decided to develop a lower-cost "maxi-pay" service: on May 18, 1980, Home Box Office Inc. announced during that year's National Cable Television Association Convention its plans to launch Cinemax, a companion movie channel designed as a direct competitor to The Movie Channel (then owned by Warner-Amex Satellite Entertainment, part-owned by Warner Bros.

As Cinemax evolved, it expanded into non-film programming content, including music specials, some limited original and acquired programming (such as SCTV Channel and Max Headroom) and, most notably, late-night softcore pornographic films and series; the adult programming—initially offered as part of the "Friday After Dark" block, eventually expanding to all seven nights by the start of the 1990s—became a key draw for Cinemax subscribers, and the main association with the channel in pop culture.

[66][67] The 1980s also saw HBO join three separate lawsuits concerning municipal and state-level statutes that would have legally prohibited cable systems from transmitting "indecent" content—specifically, programs that featured descriptions of or depicted "illicit" sexual acts and/or nudity—which Home Box Office Inc. and cable systems that challenged the laws saw as overbroad and in violation of the First Amendment, and would have precluded HBO and other pay television networks from airing programs containing material that may be considered inappropriate.

[73] A separate city ordinance in Miami that would have allowed the revocation of Miami Cablevision (now operated by Comcast)'s franchise license for carrying programs that the city manager deemed "obscene or indecent" was struck down by Judge William Hoeveler of the U.S. District Court for the Southern District of Florida on August 3, 1983, on the grounds outlined in Jenkins' ruling, and affirmed by the U.S. Court of Appeals for the Eleventh Circuit on April 10, 1985.

[76] In 1985, the operations of Home Box Office Inc. were relocated to facilities on West 42nd Street and Sixth Avenue in the Bryant Park district of Midtown Manhattan.

Towards the second half of the decade, the partnership transitioned into a singularly owned entity: CBS sold its ownership stake in the studio in November 1985,[77] followed by HBO/Time Inc. in December 1985.

Since then, the division has expanded into theatrical film productions distributed by sister company Warner Bros. Pictures and its subsidiaries, in addition to continuing to produce HBO's slate of original movies.

Throughout its 16-year existence, HIP primarily produced sitcoms for broadcast television and basic cable networks (including Martin, Roc, The Ben Stiller Show and Everybody Loves Raymond).

[87][94] HBO began taking action to ensure that their video arm would continue to have fresh product, such as an eight film co-production deal with ITC Entertainment, which gave HBO all pay cable and video rights (while ITC retained all foreign and free-to-air TV rights to the films),[95] and promotional deals designed to push rental releases.

[97] A settlement was ultimately reached that allowed HBO to offer video cassettes of the contested films for the first half of 1988, after which the rights reverted to Vestron.

The Comedy Channel's programming model was similar to the original format of MTV (which, ironically, was launched under WBD's predecessor Warner Communications and American Express's media joint venture, Warner–Amex Satellite Entertainment).

The announcement came as HBO secured an agreement with promoter Dan Duva to broadcast then-heavyweight champion Evander Holyfield's pay-cable and pay-per-view matches, which had been airing on Showtime since 1986.

[121] In 1993, HBO purchased post-theatrical distribution rights for 48 films in development from upstart production company Savoy Pictures (co-founded by Victor A. Kaufman and Lewis J.

The development of the system—inspired by the advisory ratings featured in HBO and Cinemax's respective program guides and those distributed by other participating premium cable services—was in response to concerns from parents and advocacy groups about violent content on television, allowing HBO and other services to assign individual ratings corresponding to the objectionable content depicted in specific programs (and categorized based on violence, profanity, sexuality or miscellaneous mature material).

[125] On January 7, 1998, Time Warner announced it would immediately consolidate its C-band retail businesses, HBO Direct (a retail arm of HBO's direct-to-home operations that sold HBO, Cinemax and their respective multiplex packages as well as ancillary programming services) and Turner Home Satellite (THS) (which handled C-band, direct-broadcast satellite and hospitality distribution of the Turner Broadcasting System cable networks—including TBS Superstation, CNN, CNN Headline News, CNN International, TNT, Cartoon Network and Turner Classic Movies—and until the promotion's folding in 2001, World Championship Wrestling [WCW] pay-per-view events), into a singular retail unit under Home Box Office Inc.[126] On October 15, 2014, Home Box Office, Inc. announced it would launch an over-the-top (OTT) subscription streaming service in the United States in 2015, which would be marketed directly to cord cutters (consumers who primarily use streaming video services rather than watch television via a cable or satellite subscription) and competing with services such as Netflix.

[137] On November 20, 2017, the U.S. Department of Justice filed a lawsuit against AT&T and Time Warner in an attempt to block the merger, citing antitrust concerns surrounding the transaction.

[149] On February 28, 2019, Richard Plepler stepped down from his position as CEO of Home Box Office, Inc., after a collective 27-year tenure at HBO and twelve years as head of the network and its parent unit.

Home Box Office, Inc. (encompassing HBO, Cinemax, and their respective wholly owned international channels and streaming services) was reassigned to WarnerMedia Entertainment, placing it under the same umbrella as sister basic cable networks TBS, TNT and TruTV (which were formerly part of the dissolved Turner Broadcasting System subsidiary), and under the leadership of former NBC and Showtime executive Bob Greenblatt.