Final answer:
Andrew Jackson and William Henry Harrison were the generals from the War of 1812 who later became U.S. presidents. Both used their military reputations as a foundation for their political careers. Other presidents had roles during military conflicts but were not generals in the War of 1812.
Step-by-step explanation:
The generals from the War of 1812 who later became president are Andrew Jackson and William Henry Harrison. Andrew Jackson became a national hero after his victory at the Battle of New Orleans, which significantly raised his public profile and paved the way for his presidency. William Henry Harrison also earned fame for military leadership, most notably at the Battle of Tippecanoe, which was leveraged during his political campaign with the Whigs using the slogan "Tippecanoe and Tyler too" aligning him as a war hero akin to Andrew Jackson.
Other presidents mentioned like James Monroe or James K. Polk did have roles during periods of military conflict but were not generals in the War of 1812. Monroe served as the Secretary of State and the Secretary of War under President Madison during the War of 1812 and did play a key role in the government at that time, but he did not become president because of his military service in that war. James K. Polk, while instrumental in the Mexican-American War, was not a general in the War of 1812.