Born into a wealthy ship-owning family, he is best known for founding the low-cost airline easyJet and the Stelmar shipping line with start-up funds provided by his father, Loucas.

EasyJet's foundation in 1995 marked the beginning of a series of ventures marketed under the "easy" brand, managed by easyGroup and chaired by Haji-Ioannou.

Haji-Ioannou was accused of poor maintenance and charged in Italy with manslaughter, in addition to intimidating and attempting to bribe witnesses.

Haji-Ioannou conducts business via his private investment vehicle, the easyGroup, which owns the 'easy' brand and licenses it to the various 'easy'-branded ventures, including the airline.

Haji-Ioannou continues to extend his business interests, mainly in the field of travel and leisure by encouraging entrepreneurs to adopt the "easy" brand for their companies.

Other travel/leisure-related businesses include: In September 2011 it was reported that Haji-Ioannou was working on Fastjet, a new low-cost airline serving routes within Africa, as part of a joint venture with Lonrho plc.

[15] In April 2020, Haji-Ioannou publicly called for the removal of EasyJet PLC CEO Johan Lundgren and chairman John Barton over what he describes as a "deliberate mistake" in not terminating a £4.5 billion order for 107 planes from Airbus.

He stated at the time that this appointment did not reflect his political affiliations, adding, "I agreed to be included in the group of entrepreneurs because I was assured it will be non-partisan.

"[18] In an April 2010 letter to the Daily Telegraph, Haji-Ioannou joined 23 other UK business leaders, including Marks & Spencer's Stuart Rose and Next's Simon Wolfson, criticising the Brown government's plans to raise National Insurance contribution rates.