She will join the company in September from electronic distributors Premier Farnell.
Campopiano who was voted HR magazine's HR director in 2010 has more than 20 years HR experience and has also worked with major brands in the digital and technology space including Psion (part of Motorola Solutions), Barclays Retail and Online Business.
Campopiano will report to CEO Harriet Green who she worked alongside at Premier Farnell.
"Sandra takes a leading-edge approach to all facets of people development, that means she will be instrumental in helping us build the high-performance culture we have been focused on since I joined the company a year ago," said Green
"She has deep experience of working in a multi-channel environment and developing a people strategy to support the transition of business to the web. As you know, this is one of our key strategic objectives. And she is also imbued with the experience of harnessing technology to bring real innovation to the work of her team."
Campopiano said: "Having watched the transformation of Thomas Cook over the past year, I am looking forward to being part of Harriet's leadership team as we take Thomas Cook to the next level."