At some point during or shortly after the War of 1812, David Sr. made his way to Ohio, where his family name, and the heroism of his cousin, provided ideal introductions to local society.

David Sr.'s efforts in commerce and law were no more successful in Florida than they had been in Ohio, and he left for Texas in the summer of 1835, where he quickly rose to a position of trust in the affairs of the revolutionary government, becoming a confidant of Stephen F. Austin and Sam Houston.

[5] In September 1861 he was promoted to chief engineer aboard USS Niagara (1855), which was detailed to escort the Japanese ambassadors during their return to Edo at the end of 1860.

[5] Niagara returned to American waters in April 1861, in time to be ordered as the first vessel to blockade Charleston, South Carolina, following the outbreak of armed rebellion.

[5] After the start of hostilities in 1861, he took part in the blockade of Charleston, and the bombardment of the Pensacola Navy Yard, aboard Niagara.

He was detached from Niagara in early 1862 and detailed to Boston as superintendent of the building and fitting out of the monitors Nahant, Nantucket and Canonicus.

[6] He subsequently served as chief engineer on Canonicus with the James River flotilla and later, the North Atlantic Blockading Squadron.

[6] Following the war, Macomb was on inspection duty at the then-new Philadelphia Navy Yard at League Island, assigned to laying up the bulk of the Union ironclad fleet.

[7] Macomb's retirement home was in North Cambridge, Massachusetts,[6] and he died January 27, 1911, in New York City.