[13] It was incorporated in 1935[14] and based in Dallas, Texas,[6] the company began focusing solely on telecommunications in 1999,[15] selling its natural gas assets and utility operations.

In 1969 it purchased the Kauai Electric Company, marking its then largest acquisition, at which point it operated 27 subsidiaries in five industries in around a dozen states.

After aggressively expanding the business and focusing on service quality, board member Leonard Tow was named chairman and CEO in 1990.

[31] Separate from GTE, in 1999 Citizens agreed to acquire 530,000 rural access lines from US West, a Baby Bell company, for $1.65 billion.

[48] Eight months after the acquisition, Frontier began pulling out of cable TV and offering free subscriptions to DirecTV instead, stating it had underestimated how competitive the field was.

[44] While Frontier had initially claimed it had no plans to change FiOS TV prices until 2012,[48] it substantially raised the rates in February 2011 citing rising programming costs,[49] by 50% in some regions.

It also instituted a $500 installation fee for new television subscribers[50] and began removing itself from TV franchise agreements in some cities in Oregon.

[53] Also in 2015, Frontier settled a class action lawsuit alleging slower than advertised DSL speeds in West Virginia.

Without admitting wrongdoing, Frontier agreed to invest $150 million on infrastructure in the region and provide discounted rates for affected clients until faster speeds were implemented,[54][55] which occurred in 2017.

[56] Aiming to replace the old copper system with fiber optic technology, Frontier invested another $100 million into its West Virginia network in 2023.

With revenue also declining in 2019[20] to about $8.1 billion across 29 states,[63] Bloomberg News reported in January 2020 that Frontier was "asking creditors to help craft a turnaround deal" that potentially included filing for bankruptcy.

[68] As Frontier emerged from restructuring in March 2021, it described a new focus on converting its copper-based telecom network into fiber optic cable.

[10] With John Stratton announced as executive chairman of the re-organized company in early 2021, Nick Jeffery became CEO and president effective March 4, 2021.

[4] Jeffery named a new board and executives, including Scott Beasley as CFO and Veronica Bloodworth of AT&T as chief network officer, and stated the company would focus on modernizing, "building fiber as fast as we can," and improving customer service.

[73] In January 2023, Frontier launched 5 gigabit speeds for its entire fiber network,[21] and according to Fast Company was the first nationwide internet service provider to do so.

[74] Frontier as of 2023 was active in 25 states[72] and remained focused on expanding fiber internet services and multi-gigabit speeds under its "Building Gigabit America" strategy.

[78] Frontier offers broadband internet, digital television service, and computer technical support to residential and business customers.

All of Frontier's internet plans come with unlimited data and typically don't require a contract,[9] with discounts available through the Affordable Connectivity Program.

The DSL service Frontier Internet has one plan offered with "varying" speeds depending on the residence's proximity to a local transmitting station.

[84] David Anders of CNET named Frontier Fiber 500 as the "best internet deal overall" offered by an American ISP for May 2023,[85] specifically praising the service's fast speeds, TV bundle, unlimited data, free wifi router, lack of term agreements, and suitability for online gaming.

Anders, however, described Frontier's copper DSL service as "hit or miss" due to speeds being dependent on regional infrastructure.

Anders did praise Frontier Internet's unlimited data for being a relatively rare feature for an ISP to offer in rural regions.

[72] Frontier offers services in 25 states,[9][12][86][87] including Alabama, Arizona, California, Connecticut, Florida, Georgia, Illinois, Indiana, Iowa, Michigan, Minnesota, Mississippi, Nebraska, Nevada, New Mexico, New York, North Carolina, Ohio, Pennsylvania, South Carolina, Tennessee, Texas, Utah, West Virginia, and Wisconsin.