In February 1964, the Garda Síochána moved its training school from Phoenix Park in Dublin - where it had been housed at Garda Headquarters - to McCan Barracks in Templemore, County Tipperary. The barracks itself had been built in the early nineteenth century as Richmond Barracks, a British Army installation; it was renamed for Pierce McCan, the Sinn Féin MP for Mid-Tipperary who died in Gloucester Prison in 1919. Locally the new training centre became known simply as the depot. Initially the training programme was 18 weeks long, followed by a year of on-the-job experience and then a one-month refresher; the subjects were Police Duties, Irish, and Physical Studies, the last of which consisted of physical training, drill, swimming and first aid. The curriculum has expanded considerably since.

In April 1989, after a major review of all Garda training, the institution introduced a two-year Student/Probationer programme and was renamed the Garda College. In 1992 it was designated an Institute of Higher Education by the National Council for Educational Awards; the following year, the two-year programme was accredited with the award of a National Diploma in Police Studies. The current core qualification is the Bachelor of Arts in Applied Policing, awarded by the University of Limerick. A separate Bachelor of Arts in Police Management is offered for senior officers at superintendent rank and above. The college has the capacity for 520 residents, three lecture theatres, a library of over 12,000 books, a purpose-built Scenes of Crime Room and Mock Garda Station, a courtroom, a language laboratory, and a sports complex that includes a nine-hole golf course.

The barracks the college occupies has a strange and discontinuous history. The first site selected for it in the early nineteenth century was beside the Suir at Thurles, but the Ursuline Sisters at the nearby convent objected to a military installation so close to their foundation, and the War Office moved the building to Templemore instead. In the 1850s and 1860s the Fenian Brotherhood recruited heavily among the Irish soldiers stationed here; in 1885 the entire 11th Depot Battalion was transferred out and replaced with English troops because Dublin Castle considered the local soldiers tainted with Fenianism. The Nenagh Guardian reported, with some Irish dryness, that two of the transferred soldiers were arrested in Enniskillen for singing Fenian songs. During World War I the barracks held over 2,000 German and Austrian prisoners of war; later it became a training centre for the Royal Munster Fusiliers, thousands of whom were trained here for the trenches of Passchendaele and the Somme. The trenches they practised in were later landscaped into the college's golf links.

After the Anglo-Irish Treaty in December 1921, the British Army began to leave Ireland. On 13 February 1922 the barracks at Templemore was handed over to the Irish Republican Army at a formal ceremony - Major Phibbs of the 10th Battalion Northamptonshire Regiment signing for the British forces, Commandant Sean Scott of the 2nd Battalion, 2nd Mid-Tipperary Brigade IRA signing for the Republican side. Within months the Civil War broke out; the garrison at Templemore supported the anti-Treaty side and fortified the barracks. National Army troops were preparing to attack when the Archbishop of Cashel and Emly, Dr John Harty, intervened and negotiated a peaceful evacuation. The Irish Army remained in possession until 1929. During the Second World War - the Emergency, in Irish - the 10th Southern Battalion of the Irish Army garrisoned it. The 3rd Field Artillery Regiment is still based here today, sharing the site with the Garda College.

Three medals are awarded to outstanding probationer Gardaí at the end of training. The Gary Sheehan Memorial Medal, for the best all-round probationer. The Commissioner's Medal, for the student achieving the highest aggregate academic marks across all phases. The Templemore Town Council Medal, for the student who has shown the most insight and creative engagement in Social Science Studies and made the most innovative contribution to the communities where they served on placement. Each medal frames a different idea of what a good Garda is - well-rounded, academically excellent, socially engaged - and together they suggest the institution's understanding that policing is not one thing. The recruits who win them go on to thirty- or forty-year careers in Irish policing. The recruits who don't go on to thirty- or forty-year careers anyway. About 14,000 sworn members of the Garda Síochána are currently in service. Almost all of them have walked the same corridors here at one point, in their first year, learning who they were about to become.

The town of Templemore - population about 2,800 - is shaped around its barracks. The N62 national road links it north to the M7 (Dublin-Limerick motorway) and south to Thurles and the M8 (Dublin-Cork motorway). Templemore railway station, on the main Dublin-Cork line, has frequent service in both directions and sits two kilometres from the college. To the west the R501 climbs towards the Devil's Bit mountains - the long broken ridge of Slieveardagh that gives the area its dramatic skyline. The Garda College Museum and Visitor Centre, which had run on the site from 2002 to 2020, presented the long history of Irish policing; its closure was lamented locally, though much of the collection survives. For Garda recruits arriving by train from Cork or Dublin, the walk from the station to the barracks is a kind of threshold ritual - a small Tipperary town that, for them, will always be the place where they learned to be Gardaí.