He was briefly a sailor, and spent time in Quebec, before settling in Kaskaskia, Illinois, where he studied and practiced law.

His work as auditor was criticized by a young Abraham Lincoln, who (with his then fiancée, Mary Todd) published a series of inflammatory pseudonymous letters in a local paper.

In 1845, Shields was appointed to the Illinois Supreme Court, from which he resigned to become Commissioner of the U.S. United States General Land Office.

He was educated in military science, fencing, and the French language by a veteran of the Napoleonic Wars, of which there were many in Ireland at the time.

[5]: 712 [7][8]: 26  Shields attempted to emigrate to the United States in 1822, but failed when his ship was driven aground off the coast of Scotland, leaving him one of only either three or four survivors.

Eventually, Shields settled in Kaskaskia, Randolph County, Illinois, where he studied and began practicing law in 1832, supplementing his income by teaching French.

[5]: 714 [13]: 113–5 "Rebecca" as she was, denounced Shields in the paper as a "fool as well as a liar," and scandalously described him at a party among a group of women: If I was deaf and blind I could tell him by the smell ... All the galls about town were there, and all the handsome widows, and married women, finickin about, trying to look like galls, tied as tight in the middle, and puffed out at both ends like bundles of fodder that hadn't been stacked yet, wanted stackin pretty bad ...

He was paying his money to this one and that one and tother one, and sufferin great loss because it wasn' silver instead of State paper ... [quoting Shields] "Dear girls, it is distressing, but I cannot marry you all.

[5]: 714 [k] Shields was appointed as an Illinois Supreme Court justice on February 18, 1845, to take the seat vacated by Stephen A.

He commanded the 3rd Brigade, Volunteer Division, at the battles of Vera Cruz and Cerro Gordo, where he was severely wounded by grapeshot, and spent nine weeks recuperating.

[19]: 606 Shields was again wounded, receiving a fractured arm in the Battle of Chapultepec, after his horse was shot out from underneath him, and he continued fighting on foot, and leading his troops with sword.

[5]: 716–7 [19]: 606 [n] Following the war, on August 14, 1848, he was nominated by President Polk, and confirmed by the United States Senate to serve as governor of Oregon Territory, which had been created that same day.

[5]: 717 [9]: 118 [21]: 79 As senator, he opposed slavery, and supported land grants to agricultural colleges, to railroads, to soldiers, and to settlers under a homestead act.

He arranged for Irish immigrants to move from the East Coast to Minnesota, settling in Rice and Le Sueur counties.

[5]: 719–21 When Minnesota achieved statehood in 1858, and the legislature convened in December, Shields was put forward as a compromise candidate for U.S.

He was engaged in a mining venture in Mexico, and it was there that Shields was when he was appointed as brigadier general of volunteers from that state following the outbreak of the American Civil War, succeeding the late Frederick W. Lander.

[5]: 721–4 [9]: 120 Shields was wounded at the Battle of Kernstown on March 22, 1862, but his troops inflicted the only tactical defeat of General Thomas J.

[5]: 721–724 [7] In 1863, Shields moved to San Francisco, where he would serve as the state railroad commissioner,[27] and then to the Mississippi Valley, and to Wisconsin.

In 1866 he settled in Carrollton, Missouri, which remained his home, and where he tended to his farm, lectured, and continued public involvement until his death 13 years later.

A member of Congress, Benjamin Butler, proposed him as Doorkeeper of the United States House of Representatives in 1876, but Shields, viewing it as an indignity, declined.

[5]: 726–7 [7] Shields died unexpectedly in Ottumwa, Iowa, on June 1, 1879, while on a lecture tour, after reportedly complaining of chest pains.

[8]: 330–1  His grave remained unmarked for 30 years, until the local government and the U.S. Congress funded a granite and bronze monument there in his honor.

[5]: 729 Shields was not a wealthy man in later life,[5]: 725  and upon his death the most valuable possessions he had to leave his family were his ceremonial swords, given to him following the end of the Mexican–American War.