[1] Promoted to captain, Molesworth served with his regiment at the Battle of Blenheim in August 1704, before being appointed aide-de-camp to the Duke of Marlborough on 22 May 1706 during the War of the Spanish Succession.

[2] Promoted to captain in the Coldstream Guards and lieutenant colonel in the Army on 5 May 1707, he was present at the relief of Brussels in 1708 and at the Battle of Malplaquet in September 1709 and was wounded by a mine at the Siege of Mons in October 1709.

[2] Molesworth became Lieutenant of the Ordnance in Ireland in December 1714 and was elected Member of Parliament in the Irish House of Commons for Swords in 1715.

[8] Promoted to field marshal on 3 December 1757,[9] Molesworth became Governor of the Royal Hospital Kilmainham; he died in London on 12 October 1758 and was buried in Kensington.

[10] Molesworth first married Jane Lucas, of whose family little is known; they had three children, Amelia, Letitia, and Mary, who became the second wife of Robert Rochfort, 1st Earl of Belvedere, and suffered greatly from his ill-treatment of her, which became a subject of public comment.