The Galway native had stepped away from his position as Galway United assistant manager at the start of August for health reasons.
Horgan arrived at Galway United as John Caulfield’s number two before the 2023 League of Ireland season, helping to guide the Tribesmen to a First Division title win and promotion to the Premier Division.
Prior to his spell at Eamonn Deacy Park, Horgan managed Finn Harps for 354 games from 2013 until 2022, leading the club to two successful promotion campaigns from the First Division.
Harps spent six seasons in the top-flight under his stewardship and reached an FAI Cup semi-final in his first season.
Away from football, Horgan was a maths teacher at St Eunan’s College in Letterkenny, a role he maintained despite his various coaching roles across the country.
Horgan was also involved as a coach at Donegal side Fanad United prior to joining Finn Harps, winning Ulster Senior League titles in 2006, 2007, and 2011.
Away from the professional game, Horgan also managed the FAI Schoolboys and various school teams at St Eunan’s.
Horgan was known as one of the league’s standout characters and was renowned for his tireless work ethic and dedication to the sport, often travelling hundreds of kilometres to scout opposing sides prior to facing them.
One of those opposing teams, Dundalk FC paid tribute to Horgan, who they said was a “true pillar” of the League of Ireland football community.
“We extend our heartfelt condolences to his family and friends. His contributions and achievements have left a lasting legacy, and he will be greatly missed by all who knew him.
“We will have a book of condolences at Oriel Park tomorrow night in our club shop, for those who wish to pay their respects,” they added.
Sligo Rovers, who are local rivals to both Finn Harps and Galway United, also paid tribute to Horgan, “whose passion, dedication, and commitment to football left a lasting impact. His knowledge and determination brought out the best in his teams.
“Above all, Ollie will be remembered as a man of integrity who gave his all to Irish football,” they added.
Many Irish footballing figures and fans have also taken to social media to pay tribute to a manager who was involved in several historic nights across the country.
Irish sports commentator Con Murphy paid tribute to a manager with whom he had many interactions throughout the years.
“One of the few managers who offered to make me tea 20 mins before kick off! (He was suspended at the time in fairness!) RIP Ollie.”
Other League of Ireland clubs, with whom Horgan enjoyed many memorable nights over the years, have also paid tribute to the iconic manager.
“Such sad news. Gave us Harps fans some great nights. Legend,” one fan commented.
Another tribute said the League of Ireland community has been “rocked” by the news, saying: “Remembered as a real character on the sidelines and in the media, it shouldn’t be forgotten that Ollie helped nurture young Irish talent during his time as the Ireland schoolboys’ manager, while he went on to perform heroics at Finn Harps.
“57 is no age to go, but Horgan leaves behind many wonderful memories and a true legacy as a LOI cult hero,” they added.
Funeral details for Ollie Horgan are yet to be announced.