The school was founded as St Michael's Convent in 1908 by the Sisters of the Poor Child Jesus and is now under their trusteeship.

When the Barnet LEA abolished the tripartite system, St Michael's did not turn comprehensive and has remained a grammar school to this day.

The School motto "Quis ut deus" is a Latin translation of the sarcastic rhetorical question uttered by Archangel Michael as he slew Lucifer: "Who is like God?"

It is always sung on St. Michael's Day and at various key stage certificate assemblies along with the school prayer.

After Mass, free ice cream is given out to pupils and staff in celebration of St Michael the Archangel.

These practices form part of St Michael's Catholic ethos, along with daily prayer.