Bastide was a military engineer. Commissioned as an ensign in 1711, he purchased the rank of lieutenant in 1718 and continued, as but a lieutenant, for 20 years. In 1740, he came to America as chief engineer at Annapolis Royal.
In the winter of 1744-45 he was in Boston making plans with Shirley for the colonial invasion of Louisbourg, a place, of which, he had gained considerable knowledge. He did not go directly up to Louisbourg with the colonials, but rather went back to his station at Annapolis Royal, where he was needed. On the 27th of May, with the withdrawal of the attacking forces under the Marins, Bastide sailed from Annapolis Royal to join , but by the time of his arrival the siege was all but over (June 17th) Bastide carried out limited repairs. With the hand-back of Louisbourg, in 1749, Bastide returned to Annapolis Royal to continue as its chief engineer.
Bastide was in England between August, 1751 - October, 1754. Then he was assigned to the ill fated post at Minorca. In April 1756, the French attacked Minorca and "the defences proved woefully inadequate." A lot of blame was passed around on account of Minorca (Admiral Byng was court marshalled and shot), and while Bastide might have justifiably taken some of the blame, -- "too old for his post, and crippled with gout" -- he was, the next year, 1757, promoted lieutenant-colonel.
In 1758, Bastide was appointed chief engineer in Amherst's expedition against Louisbourg. Bastide was with the troops at Halifax in the spring of the year and by the end of June he was with the British forces before the walls of Louisbourg. Apparently, the young and aggressive Wolfe did not think much of the aging engineer and was openly critical of him; at any rate, Bastide, on the 8th of July, was put out of commission, as a musket ball hit his boot, further injuring his gouty foot; he was laid up for the balance of the campaign.
In 1760, we find Bastide in the final disposition of Louisbourg; he reported to Amherst on the 28th of November, 1760, that "the demolition of its fortifications and harbour defences had been completed." In 1761 he was promoted to major-general and received orders to supervise the construction of the fortifications at Halifax. In October, 1762, Bastide returned to England.
The record shows that the old engineer got his final promotion (lieutenant-general) in 1770, and, it is speculated, that he shortly, thereafter, died.