In 1970–71, Archbishop John Charles McQuaid blessed and opened the new junior school and swimming pool.

In December 1970, Seamus Galvin was appointed the first president (1970–1976), and this was the first time St Michael's officially became an independent school and community from Blackrock College.

The following year, Cyril Sheedy became superior of St Michael's, Laurence McHugh was appointed principal of the junior school with Fr Flood[who?]

Pat Palmer dedicated the new college chapel, Cardinal Desmond Connell blessed the new building and President Mary McAleese visited the school.

[7] In 2013, St Michael's reached the Senior Cup Final with captain Ross Molony but narrowly missed out on a second consecutive victory to Blackrock College.

In 2016 St Michael's has invested heavily in on site sporting facilities and has now astro-turf all weather training, astro-turf all-weather pitch and scrummaging areas, modern weights and a gym zone, in addition to a new sports pavilion housing modern changing facilities and showers.

[8] In addition St Michael's has a number of rugby pitches and training areas located on its Dublin 4 campus.

[citation needed] Simon Keogh (class of 1998), was a member of Senior Schools Cup sides for three years up to 1998 when he also captained the first XV.

Aidan Kearney (class of 1998 and member of the 1st XV that year), played a number of seasons professionally with Leinster (2003–04) and then Ulster.

[9] As of 2020, St Michael's has more than 20 past-pupils playing professional rugby, across Ireland, the UK, France and the USA.

On 2 November 2020, a record nine St. Michael's graduates played in Leinster Rugby's Pro14 win against Glasgow Warriors in Scotstoun.

[10] This record of nine players in the matchday 23 was equaled in a European Rugby Champions Cup match against Northampton Saints in December 2020.

The junior school also enters the Cumann na mBunscol GAA league, and they won the shield in 2014.