The Italian's installation was a watershed moment, signalling the ripping up of one blueprint and the importation of a completely new philosophy intended to transform the club from top to bottom.
The speed at which Sunderland have embarked on their transfer dealings this summer, with four players in place to join on 1 July, marks them out. No Premier League side have been so active in the fortnight since the season ended.
Although Short would never say so publicly he had, for some time, been casting envious eyes up the road at Newcastle United where Graham Carr, the talented, well-connected chief scout, kept popping abroad and unearthing gifted bargains.
Concerned that a £30m investment during the last two transfer windows had produced nothing better than another relegation skirmish for Sunderland's largely British and Irish squad, Short began exploring an alternative modus operandi. He established a relationship with Roberto De Fanti, a Fifa-registered agent, and, before a 3-1 defeat at Queens Park Rangers in early March, O'Neill was introduced to a circle of Italian scouts in London as plans to overhaul Sunderland's recruitment procedures were mooted.
Barely three months later, De Fanti is poised for a new career as director of football at the Stadium of Light, where he is due to be joined by Valentino Angeloni, Internazionale's outgoing chief scout who will become technical director.
Angeloni, earlier employed at Udinese, is credited with aiding the development of Alexis Sánchez, David Pizarro, Vincenzo Iaquinta and the former Sunderland striker Asamoah Gyan.
Like De Fanti, his influence appears to have begun impacting on Wearside, with Margaret Byrne, Short's chief executive, busy negotiating a flurry of signings scheduled to be formally ratified next month. They include the Basel midfielder Cabral and two imposing defenders in Modibo Diakité and Valentin Roberge, acquired from Lazio and Marítimo respectively.
All three are available on Bosman transfers and Le Havre midfielder El-Hadji Ba, another in the same position, is believed to have agreed to join Sunderland after touring the north-east.
Having achieved record-breaking top marks in his coaching badges, Di Canio is very much a tracksuit manager who sees his primary role as "a teacher of football", spending every possible moment on the training pitch. Yet although his official title is head coach the former Swindon manager says he has the final say on transfers and believes a minimum of six new faces are required this summer.
Already the dismissal of Bryan "Pop" Robson as chief scout has heralded root-and-branch reform of the talent-spotting network while the removal of Craig Liddle, a key youth coach, signals a new direction at the academy.
Only time will tell if Sunderland are now on the right road and whether their band of Bosman imports can adapt successfully to the Premier League, but it is understood that the arrival of Di Canio, his largely Italian backroom staff and plenty of new ideas underscored by strict, European-style discipline have been broadly welcomed by the players. Adam Johnson, especially, has been enthusiastic in his praise for the former Celtic, Sheffield Wednesday and West Ham striker.
Although two players complained to the Professional Footballers' Association after Di Canio imposed numerous fines towards the end of the season, a pair of potential dissenters, Titus Bramble and Matthew Kilgallon, are out of contract and have already departed. Phil Bardsley, recently pictured lying in a bed of £50 notes in a casino, could be bound for Hull.
Di Canio remains anxious to keep Simon Mignolet but the Belgium goalkeeper is coveted by Arsenal, and Celtic's Fraser Forster has been pencilled in as first-choice replacement.
It remains to be seen how much cash Short will provide to recruit others on a shopping list featuring Fenerbahce's Serbia winger Milos Krasic. Or whether Di Canio will attempt to offload members of the squad's "old guard", most notably the captain Lee Cattermole, as he strives to provide the team with "a definite, attacking, exciting identity".
There is a single certainty: much as a new luxury Hilton hotel to be built on the banks of the Wear alongside the Stadium of Light should transform a once derelict post-industrial riverscape, Di Canio's Sunderland will be virtually unrecognisable from O'Neill's class of 2012-13.
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