The regiment saw action during the New York Campaign, Battle of Trenton, Second Battle of Trenton, and Battle of Princeton. At the Battle of Brandywine the regiment was led by Colonel James Chambers and assigned to Colonel Thomas Hartley's 1st Pennsylvania Brigade. Under the direction of acting division commander Brigadier General Anthony Wayne, the 1st Pennsylvania Regiment fought near Chadds Ford where it held the "post of honor", the far right flank of the division. At the Battle of Germantown the regiment was brigaded with the 2nd, 7th, and 10th Pennsylvania Regiments. The unit again fought on the extreme right flank of the division just east of Germantown Road. Afterward, the regiment's Major Henry Miller boasted to his family about how the division routed the British troops opposed to them and overran their camp. The 1st was in action at the Battle of Matson's Ford on December 11, 1777. That same year, Robert Blackwell became the chaplain and surgeon of the regiment—despite having no medical experience.