The Frasers spent their first North American winter, that of 1757-58, in Connecticut. In spring of 1758, the regiment joined the force being assembled for the assault of Louisbourg that led to the surrender of the fortress in July 1758. Fraser's Highlanders then moved to New York, where they were to pass the winter, but were transferred first to Boston and then, as a result of the disaster at Ticonderoga, to Albany.
Fraser's Highlanders joined General Wolfe's Quebec expedition in the spring of 1759, and served with distinction throughout the campaign. They were the only Highland troops present, and they formed the largest Regiment in Wolfe's main battle line at the Battle of the Plains of Abraham.
The Regiment remained in Quebec during the trying winter of 1759-60, and took part in the Battle at Sainte Foy on 29 April 1760. Subsequently, a detachment of the 78th accompanied General Murray's force in the advance on Montreal, where it met with the 42nd (Royal Highland) Regiment (The Black Watch) and the 77th (Montgomerie's Highlanders) Regiment, both of Amherst's force. Here, for the first time, the three Highland Regiments serving in North America during the Seven Years' War came together.