Gorham was first commissioned captain of a provincial auxiliary company in June 1744, and was promoted to lieutenant-colonel in the 7th Massachusetts provincial Infantry Regiment in February 1745. Two years later, in 1747, he was commissioned captain of an independent company in the British Army when his unit was adopted into the regular army. He is sometimes confused with his father, Shubael Gorham (born in Barnstable, Massachusetts, 2 September 1686; died at Louisbourg, Nova Scotia, 20 February 1746), a provincial colonel during King George's War. He was the one of only a handful of American rangers - including, Gorham, his younger brother Joseph Gorham, Benoni Danks, and later Robert Rogers - to earn commissions in the British Army.Grenier, 2005, p. 76. Some historians, other than Grenier, contend this argument about who received these commissions first is not only flawed but irrelevant. Dozens of Americans received commissions from the British army in King George's War and the French and Indian War. For instance, several dozen were commissioned in the 50th and 51st regiments recruited in 1754–55. Yet Rogers' commission is often singled out as exceptional. While amateur ranger enthusiasts are fascinated by this, just why it matters is unclear. John Gorham was active during King George's War and Father Le Loutre’s War.
