Roberson, who at Orange and T-Mobile-owner Everything Everywhere was director of devices, replaces Jon French, who in April was promoted to vice president of sales and operations for HTC EMEA.
HTC is ramping up its European business after opening its regional headquarters in Slough earlier this week.
French said: "I've known Phil for a number of years and am absolutely thrilled he is now joining our HTC team.
"HTC has seen tremendous growth over the last couple of years by delivering innovative and intuitive products built with consumers in mind. Phil's shrewd negotiating skills and experience in driving product strategy make him the top man for the job of further establishing HTC as the leading smartphone brand in the UK and Ireland."
HTC said it grew revenues by 93% in 2010, while HTC smartphone sales across EMEA leapt 67% year on year in the first quarter of 2011.
HTC devices use Google's Android operating system, which according to recent research is the UK's most popular smarthpone platform, with an iPhone-beating 28% market share.
Mobile phone manufacturers have gravitated towards Google's Android platform in recent years, with Sony Ericsson, Motorola, HTC, Samsung and LG all moving to the software, and consumers are now following.