Macomb was a soldier and early Texas leader. He came to Texas in 1835 after a brief stint in the US Army. He went to Gonzales where he received an appointment as the assistant adjutant and inspector general of the Texas Army. He signed the declaration of war at the Consultation of San Felipe in 1835, and then commissioned to go to New York to recruit volunteers, purchase supplies, and secure loans or donations. He was also tasked with purchasing ships for the Texas Navy. His efforts were largely unseccuessful due to a lack of funds. He returned ot Texas in July 1836 and operated a saw mill in Lynchburg, supplying lumber for the fortifications at Galveston and for ship building. He died in 1837.