When Denis founded Digicel, the company launched a GSM cellular phone service in the Caribbean. Over time, the Digicel Group extended its operations to 31 markets with revenues of over $2 billion. In 2018/2019, Digicel had more than 13 million subscribers in the Caribbean, Pacific and Central and South American regions. They have invested more than US$5b in these locations. In 2005, Digicel was one of the first operators to introduce WiMAX broadband service in the Cayman Islands and has been rolling out corporate and retail wireless broadband services throughout its markets.
Prior to Digicel, in 1991, Denis founded the Esat Telecom Group plc to compete against the former state-owned incumbent in Ireland, Eircom plc. Esat quickly established itself as the number two telecommunications company across the full spectrum of telecommunications services, including fixed-line, mobile, data and broadband. Esat was sold to British Telecom Group plc in January 2000.
Denis is one of Ireland’s leading entrepreneurs with extensive relationships across several sectors including international telecoms, radio, media, property, aircraft leasing, golf and other leisure interests. He also founded Communicorp Group, which owns and manages a portfolio of media and broadcasting-related companies in Ireland and seven other European countries. Communicorp was acquired by Bauer Media Group in 2021.
Outside of his extensive business interests, Denis is a philanthropist, which he often writes and talks about. For example, he chaired the 2003 Special Olympics World Summer Games in Ireland. It was the first time the Summer Games were staged outside the US; with teams from 160 countries and over 30,000 volunteers, the 2003 Summer Games were the most successful ever.
In 2000, he established The Iris O’Brien Foundation to identify and assist projects in Ireland and internationally which aim to alleviate disadvantaged communities. In 2004, he and other stakeholders established the Digicel Foundation, a nonprofit that helps residents in the Asia Pacific and Caribbean.
Aside from advocating for human rights through Front Line Defenders and Concern Worldwide, his most recent humanitarian effort is with The Repair Campaign. After more than two decades in the Caribbean, Denis is supporting this call to action which is seeking reparatory justice for genocide, chattel slavery and colonialism.
Denis holds a BA degree from University College Dublin and an MBA from Boston College. He provided funds to endow the Denis O’Brien Fellowship for Irish students at Boston College and is the primary benefactor of the O’Brien Centre for Science at University College Dublin.