[8] He was born at Brompton barracks, Chatham, Kent, England, on 14 November 1824[1][9] and was educated at the King's School, Rochester, and the Royal Military Academy, Woolwich from 1840.

[2]: 29  He went through the usual course of professional instruction at the military school at Chatham, of which his father was the head, and proved himself so good a surveyor and mathematician that for some months he temporarily held the appointment of instructor in surveying and astronomy.

In 1855 the new constitution came into force in Victoria, and the first responsible ministry was formed by William Haines in November 1855, General Pasley taking the portfolio of Commissioner of Public Works.

In 1856 Captain Pasley was elected to the first Victorian Legislative Assembly for South Bourke, and in March 1857 he resigned with the rest of the Ministry, but ultimately consented to remain as professional head of the Department of Public Works.

In 1860 he resigned his connection with the Public Works Department, with the intention of returning to England; but his interest in the welfare of the Colony of Victoria and of the city of Melbourne was as keen as ever in after years.

[7] Before his departure from the Colony, the New Zealand war broke out, and he immediately offered his services, which were accepted the same day, and he was appointed an extra member of Major General (afterwards Sir) Thomas Pratt's staff.

Three months later he was severely wounded by a bullet in the thigh, while in charge of the trenches, after laying out and constructing a parallel needed in the capture of the Kaihihi River pā—Mataiaio, Orongomaihangai and Pukekakariki.

In 1862 he read a paper before the Royal United Service Institution on the operations in New Zealand, to correct some misapprehensions on the subject which existed in the public mind with regard to his old general.