In business, he was noted for multiple successful roles, and became a billionaire, but by 2014, was being pursued in the Irish courts for debts amounting to €22 million by AIB, following losses amounting to hundreds of millions of euros in his unsuccessful attempt to save the Waterford Wedgwood group and to stop Denis O'Brien from assuming control of Independent News & Media.

O'Reilly's Drogheda-born father, eventually an inspector-general of customs, was born "Reilly" and added the O' when he applied to join the Irish Civil Service.

O'Reilly, named "Tony" after his mother's favourite brother, grew up on Griffith Avenue, a broad middle-class street in the Drumcondra/Glasnevin area of Dublin.

[citation needed] Educated at Belvedere College from the age of six, O'Reilly participated in several sports, including soccer, cricket, tennis, and rugby union.

He was an altar boy, and a regular attendee at chapel, and during his time there spent a summer in the Gaeltacht to improve his Irish language skills.

His Five Nations career of 15 years, 23 days is the longest in history, a record shared with fellow Ireland player Mike Gibson.

[23] O'Reilly went from college to work as a management consultant for Weston-Evans in Ashby-de-la-Zouch, Leicestershire; he earned £200 annually, which was a very good salary by the then Irish standards.

There he made his name in international business, becoming managing director of the Heinz subsidiary in the UK, its largest non-US holding and the source of half of the group's profit.

[28] O'Reilly left Heinz in 1998 after several years during which analysts questioned the company's performance, and after challenges from corporate governance groups and major pension funds including CalPERS and Business Week magazine;[29] he was succeeded by his deputy, William R. Johnson.

In the 1990s INM bought into South Africa (from 1994),[30] Australia (from 1988) and New Zealand (from 1995), acquiring 38 newspaper titles, over 70 radio stations, cable and telecoms interests at a cost of around €1.3 billion.

[31] On Friday 13 March 2009, it was announced that on O'Reilly's 73rd birthday, 7 May, he would resign as both CEO and a member of the board of INM, to be succeeded by his son, Gavin.

[citation needed] Among other investments, O'Reilly had at various times interests in: In 1996, in conjunction with his brother-in-law Petros Goulandris, he along with CEO Leonard Reinhart backed a management team that created Lockwood Financial Partners, which was named after friend Jim Lockwood who was a colleague and fee-based pioneer, and its sister company E-MAT (EMAT) which was founded by Leonard Reinhart and Jay N. Whipple to provide the first common operating program for separately managed accounts (SMAs).

He was a Pro-Chancellor of the University of Dublin from 1994 until retiring on age grounds at the end of the 2010/2011 academic year, and was also a member of the board of the Trinity Foundation.

[citation needed] They first met in New York, when Chryss accompanied her brother to a business meeting and the wedding took place in the Bahamas on 4 September 1991.

Chryss made a naming gift in her husband's honour in 1999 with the O'Reilly Theater in Pittsburgh, and he bought her a famous Jackie Onassis diamond ring for over US$2 million.

[46] A number of homes were associated with O'Reilly, including his main residence for more than 15 years, Lissadell Tamura in the private gated community of Lyford Cay, with a beach[47] near Nassau in the Bahamas.

For many years his principal residence and later a major base was Castlemartin, a "big house" dating in current form from the 18th century, at Kilcullen, County Kildare (which has associated stud farm and cattle breeding premises on the large estate lands).

O'Reilly purchased Castlemartin in 1972 from the Earl of Gowrie, and spent millions on improvements to the house and on the restoration of the 15th century Church of St Mary in the grounds.

On 15 February 2008 permission was granted for the development of two ancillary houses on a remote part of the estate, adjoining Kilcullen (Bridge) village's main street, incorporating residential, restaurant and retail space.

The £1 million house, formerly owned by railway pioneer William Dargan, was a base when travel to Castlemartin was not feasible, and a place for meetings and his private office.

[50] O'Reilly also had a holiday compound, Shorecliffe, comprising several houses, garden areas and two swimming pools, by the sea in Glandore, County Cork.

The O'Reillys also owned a château "built on the ruins of the castle where William the Conqueror plotted his 1066 invasion of England" near Deauville in France.

[47] For many years, a key O'Reilly residence was a 34-room mock Tudor house of 8,000 square feet (740 m2) at Fox Chapel, Pittsburgh, with 7 acres (28,000 m2) of grounds.

[51] The residential complex in Glandore, the house on Fitzwilliam Square and the Castlemartin Estate were all auctioned off at sales forced by O'Reilly's creditors.

[4] O'Reilly later lived in the Château des Ducs de Normandie in Bonneville-sur-Touques in France,[4][5] and later again in a house near Castlemartin in County Kildare.

The O'Reillys were significant art collectors for many years, with the biggest known acquisition being Monet's Le Portail (Soleil), bought in 2000, at Sotheby's of London, for $US24 million,[53] and others including works by William Orpen and Jack Yeats, and bronzes and statues.

In June 2008 it was reported that O'Reilly had commissioned a bound catalogue of his art collection, 15 cm thick, at a cost of €125,000 for 500 copies, edited by Suzanne Macdougald and with notes by, among others, Bruce Arnold.

Because no evidence was presented of "any operations or nontransitory economic activity in the Bahamas", the Bahamian bankruptcy would probably not be recognised for a lesser, "non-main center", argument either.

O'Reilly facilitated the project, and the author was given access to family members, including past and current wives, and to staff and business colleagues.

Titled "The Maximalist: The Rise and Fall of Tony O'Reilly", the book is said to offer an "overview of a man described by the publishers as "one of Ireland's most remarkable public figures"".