He became a captain in the Royal Navy on 10 August 1741,[1] around the age of 27. His first command was the 24-gun HMS Rye, stationed off the British Carolinas from January 1742 to February 1744.[2] In 1744 he was appointed governor and commander-in-chief of the British colony of Newfoundland, though there is no record of his visiting it during his term in office.[1] In 1745 he took command of HMS Torrington, assisting in the protection of a convoy which brought reinforcements from Gibraltar to the newly captured fortress of Louisbourg.[1]
In 1757, under the command of Vice Admiral Francis Holburne, Hardy escorted Lord Loudoun and his army from New York to Halifaxintending to attack Louisbourg, but the attack was called off when Louisbourg was found to be strongly defended by a French fleet. The next year, he was second in command under Admiral Edward Boscawen at the successful Siege of Louisbourg.[1]
Hardy served as the governor of Greenwich Hospital from 1771 to 1780. In 1778, he was made Admiral of the White. In 1779 he became Commander-in-Chief of the Channel Fleet, remaining in that post until his death in May 1780.[1]
In 1749 he married Mary Tate, however she died the next year without issue and left her home Delapré Abbey to Hardy which he sold in 1764[4] to Edward Bouverie for £22,000. Following his first wife's death, he married Catharine Stanyan,[1] the daughter of Temple Stanyan. Through Catherine, he inherited Temple Stanyan's estate at Rawlins, Oxfordshire.
The couple had three sons and two daughters. Sir Charles Hardy died at Spithead. He bequeathed £3000 to each of the sons and £4000 to each daughter,[1] as well as leaving his estate to his eldest son Temple Hardy. By Catharine's death in 1801, only Temple survived of the three sons. Hardy's brother Josiah was a merchant and the Governor of New Jersey from 1761 to 1763.