[2] Norbury was returned to the Irish Parliament for Tralee in 1773, a seat he held until 1780,[2][4] and later represented Philipstown between 1783 and 1790[2][4] and Gorey from 1790 until the Act of Union in 1801.

According to The Dictionary of National Biography "his indifference to human suffering … disgusted even those who thought the occasion called for firmness on the part of government".

[2] In 1800 he was appointed Chief Justice of the Irish Common Pleas and raised to the Peerage of Ireland as Baron Norbury, of Ballycrenode in the County of Tipperary.

Norbury's tenure as Chief Justice lasted for twenty-seven years, despite the fact that, the Dictionary of National Biography opines, "his scanty knowledge of the law, his gross partiality, his callousness, and his buffoonery, completely disqualified him for the position.

[5] In spite of this, with his strong belief in the Protestant ascendancy, he is considered to have had great influence over the government in Ireland in the early part of the nineteenth century.

[2] However, Norbury's position eventually became untenable even to his strongest supporters, especially with the British government's aim of establishing a better relationship with the Catholic majority.

Norbury survived this as well as an 1825 petition drawn up by O'Connell, which called for his removal on the grounds of him falling asleep during a murder trial and later being unable to present any account of the evidence given.

They had two sons and two daughters, including:[2] In 1797 Grace was raised to the Peerage of Ireland as Baroness Norwood, of Knockalton in the County of Tipperary, in honour of her husband.

Lord Norbury survived her by nine years and died at his Dublin home at 3 Great Denmark Street in July 1831, aged 85.