Gillett's experience spans leading the product management and development of embedded software and devices, and large scale cloud services.

Gillett has been granted a number of US[2] and international patents in the fields of security, mobile computing, networking and communications.

Having previously been a partner at Silver Lake from 2009 prior to his executive roles at Skype and Microsoft, Gillett returned to the technology private equity firm as managing director and head of value creation in late 2013.

Gillett left Microsoft in late 2013[19] and succeeded Charles Giancarlo as the Head of Value Creation at Silver Lake Partners, where he is responsible for value creation within the firm's portfolio of companies, and manages the firm's operating partner and operating executive team.

In addition to a focus on changing working practices, Gillett's leadership has been marked by radical re-design of Skype's offices,[26] most recently in the UK[27] and Czech Republic.

Gillett is reported to have led negotiations amongst the Lehman entities and administrators outside of the US[33] in early 2008 and to have worked as a part of the team until mid-2009.

[35] Gillett's re-organization of the engineering and operations team at Skype was reported as rapid, taking place in only a "short number of months", which courted some controversy and drew attention as a part of a wider criticism of Skype's stock option plan by a disgruntled former employee.