IAC was established in 1986 as Silver King Broadcasting Company, as part of a plan to increase viewership of the Home Shopping Network (HSN) by purchasing local television stations. By 1988, Silver King had bought 11 stations for about $220 million. The company was later renamed as HSN Communications, Inc., and then Silver King Communications, Inc. In 1992, Silver King was spun off to HSN shareholders as a separately traded public company. In August 1995, Barry Diller acquired control of Silver King, in a deal backed by the company's largest shareholder, Liberty Media. Diller, who had led the creation of the Fox network, reportedly hoped to use Silver King's stations as the foundation for a new broadcast network.
The company acquired several assets in the late 1990s. In December 1996, Silver King acquired an 80% stake in HSN for $1.3 billion in stock, and changed its own name to HSN, Inc. At the same time, the company acquired Savoy Pictures, a failed film studio that owned four Fox affiliate stations through SF Broadcasting, for $210 million in stock.
USA Networks merged the online division of Ticketmaster with city guide website CitySearch in September 1998, establishing a new company that went public as Ticketmaster Online-CitySearch (TMCS). USA then sold Ticketmaster proper to TMCS in 2001, retaining a 61 percent share in the combined company, which became known as simply Ticketmaster. USA brought Ticketmaster back under full ownership in 2003, purchasing all outstanding shares.
In the early 2000s, USA Networks began divesting itself of its traditional television broadcasting and production units. In May 2001, Univision Communications acquired USA Broadcasting (a division of USA Networks including 13 local stations). The next year, Vivendi bought the rest of USA's broadcast entertainment businesses, including the USA Network and Sci-Fi Channel. This led to the creation of a new company named Vivendi Universal Entertainment, led by Diller. Throughout this transition, USA Networks continued to build up its online portfolio. In July 2001, the company entered the online travel business with its acquisition of Expedia, followed the next year by an acquisition of Interval International.
Following the shift in focus to online assets, the company changed its name to USA Interactive (USAI) in May 2002;InterActiveCorp in June 2003; and finally to IAC/InterActiveCorp in July 2004.
In August 2003, IAC acquired the online mortgage comparison site LendingTree, and in September, the company added discount travel website Hotwire.com to its growing list of acquisitions. In October, IAC agreed to buy French travel site Anyway.com from Transat A.T. for $62.7 million.
In May 2008, IAC and Ask.com acquired Lexico, the owner of Dictionary.com, Thesaurus.com, and Reference.com. In August 2008, IAC spun off several of its businesses, including: Tree.com (formerly LendingTree), the Home Shopping Network, Ticketmaster, and Interval International.
IAC's largest shareholder, Liberty Media, exited the company in 2010, following a protracted dispute over the 2008 spinoffs. Liberty traded its IAC stock for $220 million in cash, plus ownership of Evite and Gifts.com. On the same day, Diller stepped down as CEO, though he remained as chairman and Match.com CEO Greg Blatt was appointed to succeed him. That same year, IAC acquired dating site Singlesnet and fitness site DailyBurn.
In January 2013, IAC acquired online tutoring firm Tutor.com. On August 3, 2013, IAC sold Newsweek to the International Business Times on undisclosed terms. On December 22, 2013, IAC fired their Director of Corporate Communications, Justine Sacco after an AIDS joke she posted to Twitter went viral, being re-tweeted and scorned around the world. The incident became a byword for the need for people to be cautious about what they post on social media.
In 2014, IAC acquired ASKfm for an undisclosed sum.
November 2015, IAC and Match Group announced the closing of Match Group's previously announced initial public offering. 
In May 2017, HomeAdvisor combined with Angie's List, forming the new publicly traded company ANGI Homeservices Inc. The company made its stock market debut in October 2017. In October 2018, the ANGI made its first acquisition of on-demand platform Handy.
In July 2019, IAC made its largest investment ever in the world's largest peer-to-peer car sharing marketplace, Turo. Later that year, IAC acquired Care.com.  In December 2019, IAC and Match Group entered into an agreement providing for the full separation of Match Group from the remaining businesses of IAC. 
In January 2020, IAC withdrew its financial backing for CollegeHumor and its sister websites and sold the websites to Chief Creative Officer Sam Reich. As a result of the restructuring, more than 100 employees of CollegeHumor were laid off. In February, IAC completed its $500 million acquisition of Care.com 
In July 2020, IAC and Match Group announced the successful completion of the separation of Match Group from the remaining businesses of IAC. As a result of the separation, Match Group's dual class voting structure was eliminated and the interest in Match Group formerly held by IAC is now held directly by IAC's shareholders. As of the separation, "new" IAC trades under the symbol "IAC" and "new" Match Group under the symbol "MTCH." 
IAC's businesses are categorized into distinct segments for the purposes of financial reporting. Those segments are labelled by the company as ANGI Homeservices Inc., Vimeo, Dotdash, Search, and Emerging and Other. Each business listed may have multiple brands connected to it.
ANGI Homeservices Inc.
On May 1, 2017, IAC announced it had entered into a definitive agreement with Angie's List to combine HomeAdvisor, a digital marketplace for maintenance and repair services, and Angie's List into a new publicly traded company named ANGI Homeservices Inc.