George Kirwan was born around January, 1860, in Hackney, London, to parents George and Rachel. His father was a travelling salesman for a toy manufacturer.

His mother died when when he was only 5, and his father died three years later so, at the age of 8, he entered the Commercial Travellers' School for Orphan and Necessitous Children in Pinner, a school set up for the children of travellers who died on the road. He later went on to the City of London School, and matriculated in 1879 after which he entered St Catherine's College, Cambridge

He emerged with a BA in 1883, and started his teaching career at The Wick Private School, Brighton. In 1885 he moved to Paris for six months, returning in 1886 to teach at Coatham Grammar School, in Redcar.

In 1888 he gained his MA, and moved to Wyggeston School, Leicester. After seven years he became Assistant Director of Leicester Technical School.

When Dakyns left the High School in 1896 to go to Morpeth, Kirwan was appointed to replace him as Headmaster. His main subjects were mathematics and languages and, as the Shields Gazette described him, he was "an exemplary head teacher".

Kirwan had to steer the school through difficult financial times. First of all, the school was bankrupt when it had failed to attract enough pupils, and then the company which owned the school gave it up and sold it to the local authority. These difficulties led him, in 1901, to apply for the post of Headmaster at Carlisle Grammar School, but he failed to be selected.

In 1919, he took ill and requested a leave of absence in order to undertake a course of treatment. Sadly, he died a month before he was scheduled to take it. At his funeral, some sixty High School Cadets led the hearse, followed by a large number of boys from the school.

In 1935, his son, Geoffrey Dugdale Kirwan, donated £100 to establish prizes in his father's memory. For many years afterwards, the Kirwan Prize was awarded for Latin, French and General Knowledge, and his name was given to Kirwan House.