In 1771, he joined the
42nd Highlanders; then switched to the
17th Foot and was promoted to lieutenant in 1773, and to captain in 1776. Sent to America in 1776, he served in the
Battle of Long Island and the
Battle of Fort Washington. Leslie was one of many who died during the
Battle of Princeton on 3 January 1777. According to Lieutenant William Armstrong of the 17th Regiment, Leslie "fell in the first fire." Surgeon Andrew Wardrop, also of the 17th, stated that "no sooner [he'd] received the shots than he instantly expired without a groan." The British put his body in a wagon that was later taken by the Americans, Leslie's body was identified by General Thomas Mifflin. The following day his friend Benjamin Rush learned of Leslie's death from British Captain John McPherson while treating the wounded at Princeton. On 5 January at
Pluckemin, General
George Washington ordered military honors for the burial when he learned Leslie was a friend of Rush. The gravestone is in the graveyard of the former St. Paul's Lutheran Church (built 1757), where the Pluckemin Presbyterian Church is now located. == Legacy ==