His father, Rev George Leslie Gresson, was rector of Ardnurcher in County Westmeath.

[1] Together with his colleague Edward Hartson Burroughs, he published a book on Irish equity pleading.

[6] The family made their way over the Bridle Path on foot to their home in Christchurch, but their luggage was shipped and lost on the Sumner bar, including Gresson's legal library.

[7] He served on various executive councils under the leadership of John Hall (1854–1855), Joseph Brittan (1855), Tancred (1855–1857 and 1857–1858), Richard Packer (1867), Charles Bowen (1867), and Thomas Cass (1867).

[1] Prior to that, Justice Sidney Stephen[10] sometimes visited the South Island in judicial matters.

[4] On 4 September 1858, Governor Thomas Gore Browne appointed Gresson judge of the Supreme Court.

After gold was found in Central Otago, a separate judge was appointed for the area south of the Waitaki River.

Gresson led the opposition of New Zealand's judges to this interference and even went to Wellington, but to no avail.

In early 1875, three of New Zealand's five judges resigned over this affair: Gresson, Chapman, and Chief Justice Arney.

It is obvious that such a power is open to gross abuse, and that if these be the terms on which they hold office, the Judges are not better off than when their commission was only during pleasure.Gresson's strong stance has since been the acknowledged reason for maintaining the independence of the New Zealand judiciary.

[18] They then lived in Oxford Terrace East, from where Gresson began his legal work.