After constructing some improvements, his father sold the farm in Jay and moved the family to a new plot of land in Champlain, New York, in 1805.

In 1808, he boarded at Champlain, New York, and attended a school taught by William Beaumont, which he credited as greatly improving his grammar and general knowledge.

[2] At the outbreak of the War of 1812, his employer became a sutler for the United States Army attached to the command of General George Izard.

After a dispute with his employer, he quit that position and went to work for another sutler, this one attached to the 2nd Regiment of Light Dragoons at Avon, New York.

[1] While there, in April 1815, he received a letter from Louis Rouse, a merchant from Green Bay, offering to employ Lockwood as his assistant suttling for the Consolidated Regiment of Riflemen.

From Detroit, they shared a schooner with trader Ramsay Crooks on a trade assignment for John Jacob Astor.

[1] They arrived at the small trade depot of Green Bay in July 1816, where the regiment set about establishing a fort—later known as Fort Howard.

[2] In May 1824, at the first session of the court at Prairie du Chien, Lockwood was admitted to the bar and named prosecuting attorney.