Vaizey has been a member of FTI's Technology Media and Telecommunications Advisory Board since March. He will begin his new role after the general election.
He was elected MP for Wantage in 2005, served as a minister from 2010 to 2016, with responsibilities for the Departments for Culture, Media and Sport (DCMS) and for Business, Innovation and Skills (BIS).
Between July 2014 until July 2016 he was responsible for the digital industries until he returned to the backbenches after a cabinet reshuffle under former prime minister Theresa May.
He decided earlier this month that he would not contest the 2019 general election.
Vaizey told PRWeek he has known and admired FTI Consulting for some time and wanted a role that allowed him to continue working in the technology, media and telecoms sector.
He said he joins FTI Consulting at one of the most important times for the rapidly evolving tech, media and telco industries, with new regulations widely predicted. His role will be to help clients in those sectors better navigate these changes.
"Technology companies are very aware that regulation [is likely] and now they are willing participants [in this discussion]. Five years ago when I was technology minister, that might not have been the case," he said.
Vaizey said there are "legitimate concerns" about how tech companies are regulated in relation to privacy, artificial intelligence and other areas.
Outside of politics, Vaizey is a supporter and ambassador to the arts and after leaving his ministerial role became a became a trustee of the National Youth Theatre and the international charity BritDoc and London Music Masters.
FTI strengthened its digital practice last week, with the appointment of Centrica's director of digital communications Laura Price.