In the early 1850s, he, along with his partner, B. F. Moore, grew to monopolize the entire steamboat fleet on Lake Winnebago and the Fox and Wolf rivers.
Wisconsin received word of the Battle of Fort Sumter during his first month in office; Fitzgerald immediately called a war meeting in the city, where the first company of Oshkosh volunteers were raised for service in the American Civil War—the Oshkosh volunteers became Company E of the 2nd Wisconsin Infantry Regiment.
[4] He sought the Democratic nomination for Wisconsin's 3rd congressional district in 1860, opposing the renomination of incumbent Charles H. Larrabee, but was unsuccessful in his attempt.
[5][1]: 296 Fitzgerald was apparently an extremely successful businessman; according to contemporary accounts, his estate was worth approximately $500,000 at the time of his death, which would be about $10.5 million adjusted for inflation to 2020.
Just after midnight that evening, Fitzgerald apparently wrote eight letters to his wife, friends, and business partners, and killed himself with a pistol.