Mignot's parents, who were staunch supporters of Napoleon, came to America in 1815 following the Bourbon restoration. Louis, whose name seems to contradict his family's political leanings, expressed an early interest in a career in art and, in 1851, he went to Holland to do just that. He studied at The Hague under Andreas Schelfhout, subsequently traveled through Europe, and returned to America in 1855 [CHECK THIS DATE: HIS ADDRESS IN NAD CATALOGUE 1853 IS HUDSON ST NYC]. Already an admirer of Frederic Church, he gladly accepted an invitation to accompany the older artist on his second trip to Ecuador in 1857, a journey which assured Mignot's reputation as a landscapist.
Following his return to America, Mignot took rooms at the Tenth Street Studio Building in New York. With the outbreak of the Civil War, however, he found that his southern sympathies made it impossible for him to remain in that northern city. On earnings he garnered from the sale of forty-six of his paintings in June, 1862, he left America, hoping to eventually make his way to India and the Himalayas. These rather unconventional plans were never realized and Mignot remained in England for the rest of his life except for short trips to the Continent. On the last of these, in 1870, he was forced to flee Paris at the outbreak of the Franco-Prussian War, but not before he contacted the small-pox which killed him almost as he stepped ashore in England. A large memorial exhibition of his works was held in London and then shown at the Pavilion, Brighton, in 1876.
Mignot first exhibited at the National Academy in 1853, showing three paintings based on his early European travels. He continued to exhibit here for the rest of the decade and until the beginning of his expatriation in 1862. The catalogues of the Academy's exhibitions from these years reveal that Mignot collaborated on several works with John W. Ehninger and Eastman Johnson who provided the figures to grace Mignot's landscapes. It is also known that Mignot provided background landscapes for several of Thomas P. Rossiter's historic scenes set at Mount Vernon.
Mignot's early death prompted the following tribute in the Academy's Minutes: "Resolved, that in the decease of our late friend and fellow Academician, we mourn the loss to the Academy of one of its ablest members, and one whose genius as a Landscape Painter has contributed greatly to the attainment of the distinguished position which his department of art now occupies amongst us."
