Momentum Telecom, provider of IP voice, unified communications and cloud-based managed solutions, has named William Fox, a former chief financial officer and investment banker, to succeed company founder Alan Creighton, as president and chief executive.

Creighton, who launched Momentum in 2001 as a traditional telephony service provider and presided over the company’s transformation to IP voice and cloud services as its first and sole chief, will remain on Momentum’s board and assist in Fox’s transition to the top spot.

Momentum maintains some 100,000 digital voice lines for more than 350 independent cable operators, municipalities, value added resellers, managed service providers and direct subscribers in the United States. In the last year, Momentum said it has tripled the size of its VAR network and opened regional sales and engineering offices in key markets, including Boston, Denver, Los Angeles/Orange County, Nashville, Dallas, Chicago, Miami and Birmingham. The company maintains 10 offices in the United States.

Fox, who served as Momentum’s interim CFO in 2011 in his three years of experience with the company, has had a hand in its merger and acquisition strategy and holds a seat on the board. He brings a lengthy business background to his new job, having previously served as CFO at SuccessEHS, a health IT vendor specializing in practice management and EHR software solutions, and as an investment banker with Lincoln International, specializing in debt capital financings for midmarket leveraged buyouts. He also worked at tax consultant PricewaterhouseCoopers.

“I look forward to building upon Momentum’s first-class technology infrastructure, its reputation for reliability and customer service, and its growing brand recognition throughout the United States,” said Fox.

Momentum claims a 500 percent year-over-year growth rate for new sales to businesses and its board recently approved a substantial hike in resources devoted to the effort, a commitment not lost on Fox. “This investment from the board shows a strong commitment and enthusiasm from our stakeholders, and I believe that Momentum is in an incredibly strong position in the communications industry,” he said.

Fox is the second executive from SuccessEHS to have joined Momentum. In May, Elizabeth Pharo, SuccessEHS chairperson, joined Momentum as the head of its board, building on a relationship between the two companies that began in 2011 with a joint venture.

“On behalf of everyone at Momentum, I would like to express our thanks to Alan [Creighton],” said Pharo. “He has been instrumental in growing the company, its product portfolio and customer base,” she said.