In 1994, T-Mobile United States was established as VoiceStream Wireless PCS, a subsidiary of Western Wireless Corporation.

Jamie Lee Curtis served as the spokesperson for VoiceStream Wireless since 1998, promoting the company's advertising slogan 'Get more from life'.

VoiceStream Wireless was spun off from its parent company Western Wireless on May 3, 1999.

In 2000, VoiceStream Wireless acquired two regional GSM carriers.

Deutsche Telekom completed its acquisition of VoiceStream Wireless, Inc., for $35 billion and Southern U.S. regional GSM network operator Powertel, Inc., for $24 billion in June 2001.

Deutsche Telekom purchased VoiceStream Wireless in 2001 and rebranded it as T-Mobile on September 4, 2002. This marked a significant milestone in the company's history, transitioning from VoiceStream to T-Mobile.

Since 2004, T-Mobile has been winning multiple J.D. Power annual awards for retail sales satisfaction, wireless customer care, and overall customer satisfaction, showcasing its commitment to customer service excellence.

T-Mobile USA emerged as the successful bidder in 120 license auctions, securing nationwide coverage of 1.7 GHz and 2.1 GHz frequencies. The company also acquired additional licenses in key areas like New York City, Chicago, and Boston.

T-Mobile announced the acquisition of regional GSM carrier SunCom Wireless Holdings, Inc. for $2.4 billion on September 17, 2007. The acquisition was completed on February 22, 2008, adding 1.1 million customers to T-Mobile's base and expanding its network coverage.

T-Mobile officially activated its 3G network in the New York City market, providing customers with enhanced mobile data services.

In late May 2009, Catherine Zeta-Jones returned as a T-Mobile spokesperson for a 'Mobile Makeovers' advertising campaign.

T-Mobile revealed plans to enhance its network by upgrading from HSPA+ 21 to HSPA+ 42, aiming to provide faster and more efficient mobile data services to its customers.

On June 29, 2010, T-Mobile introduced voice service in the Gulf of Mexico through a roaming agreement with Broadpoint. This initiative marked a step towards expanding T-Mobile's network coverage and services.

On March 20, 2011, AT&T announced its intention to buy T-Mobile USA for $39 billion from Deutsche Telekom. The deal would make AT&T the largest mobile phone company in the United States with a 43% market share.

On August 26, 2011, the FCC restarted the 180-day timer for making a decision on AT&T's purchase of T-Mobile. The decision was expected around December 4, 2011.

On August 31, 2011, the Antitrust Division of the United States Department of Justice formally announced that it would seek to block AT&T's takeover of T-Mobile USA and filed a lawsuit in federal court to prevent the acquisition.

On November 22, 2011, tmonews.com reported that the FCC was opposed to the merger between AT&T and T-Mobile.

On November 23, 2011, The Wall Street Journal reported that the FCC added an extra review process for AT&T's acquisition of T-Mobile, putting the deal in deeper jeopardy.

The FCC released a staff report on November 26, 2011, stating that the proposed AT&T-T-Mobile merger would likely harm competition and consumer interests, recommending a hearing on the matter.

On December 1, 2011, Carly Foulkes and a group of 100 Chicago-area women performed a flash-mob style dance at Woodfield Mall, which was filmed and turned into a successful holiday commercial.

AT&T abandoned its bid to purchase T-Mobile USA on December 19, 2011, after facing regulatory challenges and opposition. The decision marked the end of the acquisition attempt.

During the Q4 Earnings Call, T-Mobile announced plans to roll out LTE network on AWS spectrum and transition HSPA+ network to PCS band.

The FCC approved a deal between T-Mobile and Verizon in which T-Mobile gained additional AWS spectrum licenses in 125 Cellular Market Areas.

GoSmart Mobile, a T-Mobile branded service, was launched in beta on December 7, 2012, offering no-contract SIM wireless services. It later became available nationwide on February 19, 2013.

T-Mobile started rolling out LTE in 7 markets including Baltimore, San Jose, Washington, D.C., Phoenix, Las Vegas, Kansas City, and Houston.

MetroPCS Communications merged with T-Mobile USA on May 1, 2013. The merger allowed T-Mobile to access more spectrum and financial resources, expanding its LTE network and making it the fourth-largest carrier in the United States.

T-Mobile agreed to buy wireless spectrum for the Mississippi Valley region from U.S. Cellular for around $308 million on June 28, 2013, expanding its 4G network across 29 more markets.

On October 9, 2013, T-Mobile launched the Simple Global service, allowing customers to roam in over 100 countries with certain benefits. This service provided international connectivity and enhanced communication options for T-Mobile users.

T-Mobile signed agreements with Verizon Wireless on January 6, 2014, to purchase 700 MHz A-Block spectrum licenses for $2.365 billion. This acquisition provided T-Mobile with additional coverage in key U.S. markets.

In January 22, 2014, T-Mobile ventured into banking by offering Visa cards with banking features and a money management app for reduced-fee services. However, the banking cards were discontinued in early 2016.

T-Mobile announced that its 4G LTE network covered 209 million people in 273 metro areas and planned to roll out 700 MHz A-Block spectrum by the end of 2014.

T-Mobile announced a plan to upgrade its entire 2G/EDGE network to 4G LTE, expecting 50% completion by the end of 2014.

T-Mobile announced that their 4G LTE network covered 260 million people and rolled out 700 MHz Band 12 LTE in several cities.

On July 15, 2015, T-Mobile introduced the Mobile Without Borders service, enabling users to utilize their voice, text, and data plans while roaming in Mexico and Canada. This service aimed to provide seamless connectivity for T-Mobile customers traveling across borders.

On August 31, 2015, T-Mobile announced measures to cap unlimited data users who abuse tethering, leading to throttling speeds for those users.

T-Mobile announced in its Q3 2015 earnings call that they covered over 300 million people with LTE, reaching their 2015 end of year goal months ahead of schedule.

T-Mobile announced the purchase of the 700Mhz A-block license for the Chicago metro area, expanding their LTE network coverage.

As of October 7, 2016, about a quarter of T-Mobile's overall account numbers have moved over to T-Mobile One, the new family plan offering unlimited talk, text, and data with limited video streaming.

T-Mobile began the rollout of LTE on the 600 MHz band, expanding their network coverage.

T-Mobile introduced the Netflix On Us program on September 12, 2017, initially limited to T-Mobile ONE family plans. It included the Standard ad-free Netflix plan, valued at $11/month after an October 2017 price increase.

In October 2017, T-Mobile revealed plans to cap LTE-speeds at 5 GB starting November 12, 2017, while maintaining unlimited data roaming in Canada and Mexico. Additionally, T-Mobile announced a partnership with US Cellular to expand 4G LTE coverage in California, Iowa, Washington, and Wisconsin.

On December 13, 2017, T-Mobile announced the acquisition of Layer3 TV to launch its own subscription television service, later re-branded as TVision Home. The service included various packages like TVision Vibe, TVision Live, and TVision Channels.

On April 29, 2018, T-Mobile US and Sprint Corporation announced their intention to merge. The merger faced legal challenges but was eventually approved, leading to the discontinuation of the Sprint brand and the integration of both companies.

On January 1, 2019, Safeco Field was renamed to T-Mobile Park after T-Mobile US signed a naming rights contract with Major League Baseball's Seattle Mariners.

As of January 22, 2019, T-Mobile deployed the LTE-Advanced upgrade in 6,000 cities and towns, improving network capabilities.

On June 2, 2019, T-Mobile launched the Magenta plan, replacing the T-Mobile ONE plans. The Magenta plan included features like 3 GB of mobile hotspot data for standard plans and enhanced HD streaming.

As of October 28, 2019, T-Mobile's LTE network covered 326 million people, increasing their network reach.

By February 6, 2020, T-Mobile's 600 MHz network covered 8,900 cities and towns, providing LTE coverage to 248 million people.

On February 11, 2020, District Judge Victor Marrero ruled in favor of the T-Mobile and Sprint merger, stating that it would not substantially lessen competition as claimed by some states. The decision paved the way for the merger to proceed.

The merger between T-Mobile and Sprint officially closed on April 1, 2020. Following the closure, the Sprint brand was discontinued, and various operational changes were implemented to integrate the two companies.

In an April 10 blog post, T-Mobile CEO Mike Sievert highlighted the progress made by the carrier in the three years since the merger with Sprint. The post emphasized advancements in 5G services, home internet availability, and competitive pricing.

On April 21, 2020, T-Mobile introduced Ultra-Capacity 5G in Philadelphia using the spectrum obtained from the Sprint merger. This new 5G network aimed to provide faster speeds and better coverage in the area.

On August 2, 2020, the Sprint brand was officially discontinued following the closure of the merger with T-Mobile. This marked a significant milestone in the integration process of the two companies.

On January 15, 2021, T-Mobile changed the Netflix On Us benefit for Magenta subscribers to the Netflix Basic plan for Magenta subscribers and the Netflix Standard plan for Magenta Plus and ONE Plus subscribers.

On January 22, 2021, T-Mobile unveiled the Magenta MAX plan, offering unlimited Premium Data, 4K UHD video streaming, and various other features. The plan cost $57 per line per month for three lines.

On August 16, 2021, T-Mobile confirmed a data breach where hackers claimed to have accessed 'full customer info' from T-Mobile servers.

On August 18, 2021, T-Mobile provided an update on the data breach revealing that sensitive personal information of over 40 million former and prospective customers and 7.8 million existing postpaid customers was accessed by hackers.

Multiple class-action lawsuits were filed against T-Mobile on August 23, 2021, due to the cyberattack impacting both current and former customers. The lawsuits accused T-Mobile of negligence and putting customers at risk.

On August 24, 2021, T-Mobile announced that T-Mobile Business customers were affected by the data breach, with varying types of business and personal information accessed.

On September 6, 2021, T-Mobile US customers filed class action lawsuits accusing the company of negligence following the data breach incident, citing violations of cybersecurity guidelines and privacy acts.

On January 31, 2022, T-Mobile participated in Auction 110 by the FCC to bid on C-Band 3.45 GHz licenses. This strategic move aimed to expand their network coverage to reach up to 184 million people across the United States, positioning T-Mobile as a key player in the 5G market.

T-Mobile officially discontinued its UMTS network on July 1, 2022, marking the end of an era and signaling a shift towards more advanced technologies.

T-Mobile announced its acquisition of Ultra Mobile on March 15, 2023.

On April 20, T-Mobile revealed the Go5G plans and Essential Saver plan. The date 4/20 was referenced, and T-Mobile aimed to 'smoke the competition' with these new offerings.

As of January 24, 2024, all T-Mobile subscribers with the Netflix On Us benefit receive the ad-supported Standard plan from Netflix, regardless of their T-Mobile plan. This plan is missing several titles compared to ad-free plans.