william leitch
In a biography of James Leitch, there is small biography of his father William Leitch. It reads:
“and is a son of William Leitch, who was born at Ardrossan, Ayrshire, Scotland. William Leitch came to Canada when sixteen years of age (1832), and served in the Stormont Militia under Col Vankoughnet, during the Rebellion of 1837-8.”[A Cyclopaedia of Canadian Biography: Being Chiefly Men of the Time, George Maclean Rose, ed., Toronto, Rose Publishing Company, 1886, p. 646]

A similar narrative appears in “A Standard Dictionary of Canadian Biography: The Canadian Who was Who, vol 1,” Charles GD Roberts & Arthur L Tunnel eds., Toronto, Trans-Canada Press, 1934, p. 300. So where to look to ascertain this as truth? Ancestry.ca actually has the muster rolls for the British Army and Canadian Militia online, so I googled William Leitch. The rolls actually have him listed under the 1st, 2nd, and 3rd Provisional Battalion, 4th Provisional Battalion (Glengarry Highlanders) 5th Provisional Battalion.

More specifically the books list him under the 6th Company, 3rd Provisional Battalion of Militia under the command of Lieut Col the Hon Philip VanKoughnet. He served from at least from May 1838 to April 1839.
I guess the last question I had to ask was what did he do when he served, did he fight, did he go to Lower Canada, or did he patrol in his home area?

For this I researched VanKoughnet, his commanding officer to find out where he was, because by association, you know that is where his soldiers were. And to answer the question, yes, William Leitch appears to have seen actual battle. His group were at Prescott, Ontario in November 1838, and repelled the attack of the Hunter Patriots at the Battle of the Windmill, at Windmill Point.

Battle of Windmill Point, contemporary image, Wikipedia
Battle of Windmill Point, contemporary image, Wikipedia