John Legere has leveraged his own considerable charisma to bring attention to T-Mobile (NASDAQ:TMUS) and turn the company from an also-ran to a rising contender in the wireless phone space dominated by AT&T (NYSE:T) and Verizon (NYSE:VZ). The CEO's bravado and social media swagger have turned the company into the fastest growing wireless company and brought it to the cusp of catching Sprint (NYSE:S) for third place in customers served.

All four companies have reported third-quarter results and T-Mobile added 1.2 million contracted customers, which is more than Verizon and AT&T combined, according to GeekWire.. Sprint actually lost half a million contract customers for the period, narrowing its lead over Legere's company to about 2 million customers (55 million for Sprint to 52.9 million for T-Mobile).

Legere has been able to deliver this tremendous growth partially by radically changing his company's business model to include more transparency and better pricing and partially by calling out his competitors. T-Mobile may be the best overall value for consumers, but winning subscribers requires letting them know that. Legere has been a master at publicizing where his competitors are dropping the ball, shading the truth, and generally not being square with customers.

Legere's Twitter feed often reads more like he's a boastful rapper than a corporate CEO with tweets like this being indicative of his tone.

#sorrynotsorry is not something you would see a typical CEO use, but Legere's brashness has won him nearly 700,000 Twitter followers, many of whom actively help spread the T-Mobile gospel. One of the key things Legere uses social media for is sharing negative information about his competitors.

AT&T's Next 24 is misnamed
Legere loves to go after AT&T and a recent swipe at the company points out how silly it is that its Next 24 plan is in fact a 30-month installment program.

The plan does allow AT&T customers to turn in their phones for a new one after 24 months, but they won't actually own them until 30 months worth of payments are made (and the name is truly ridiculous).

He doesn't believe Sprint can compete
Once a potential merger with Sprint fell through Legere took the gloves off and began using the #SprintLikeHell hashtag on Twitter. His many, many posts on his rival made it clear that he believes his company will pass it for the No. 3 spot and that any growth Sprint has will not come at the expense of T-Mobile.

Based on the third-quarter numbers, Legere's skepticism about Sprint's potential growth was well-founded. Not only is the company not taking customers from T-Mobile, it's not taking customers from any of its rivals as it lost subscribers for the period.

Legere doesn't think you should trust Verizon or AT&T
One of Legere's main strategies has been to dub his company the "Un-Carrier" and pledge to do things in a different way than wireless companies have traditionally. To him that means no more obscuring what people will be paying or doing other things that customers are not likely to want.

Basically, Legere acts like Batman for the wireless customer. Every time his competitors make a new claim or offer, he exposes the loopholes, hidden fees, and other potential problems. Of course he's biased toward his own company, but he's also forced to be honest because if he's caught in a lie or even shading the truth, it could topple T-Mobile's entire strategy.

Legere has built his company around the idea that T-Mobile is the only honest wireless carrier. His Twitter attacks can be a little boorish, but they essentially put his money where his mouth is. If Legere accuses his rivals of something, by extension T-Mobile has to act in the opposite fashion.

It's a compelling digital play which shows that promises made in commercials are meaningless unless you actually deliver in real life. If subscriber counts are to be believed, Legere has delivered by doing things differently and calling out his competitors for acting as they always have.

Daniel Kline owns shares of Apple. He is a Sprint customer who has considered switching to T-Mobile. The Motley Fool recommends Apple and Twitter. The Motley Fool owns shares of Apple and Twitter. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.