Rosseau was born in Pointe Coupée Parish, LA, on 21 September 1859. Rosseau's family was of French descent and operated a farm, originally based on a land grant from Louis XIV in the Louisiana territory, until the outbreak of the Civil War. During the war, Rosseau's father and two older brothers were killed; his mother had also died, and the Union General W. T. Sherman laid ruin to the family holdings during the Mississippi campaign. Rosseau and his sister were rescued by a slave and the two were raised by a family friend in Kentucky. Rosseau was educated in a private school and taught to shoot and fish by his guardian. He began working at seventeen, trying his hand at various trades to earn a living for himself and a dowry for his sister. He worked as a cowboy and cattle driver in Texas and along the Chisholm Trail from Mexico to Kansas for six years. The Panhandle of Texas in which he worked cattle was abundant in wild game, especially the Texas panther, or mountain lion, which prompted Rosseau in 1878 to send for hounds from Louisiana of the same French bloodlines originally from Normandy, the Franc Comptoise, that his ancestors had imported at the time of the original land grant. Rosseau developed a pack with these hounds and hunted the panther for a number of years, until he left the area in the early 1880s, at which time he gave approximately thirty couple to various local ranchmen. These hounds were, without a doubt, the first scenting pack hunted in the Southwest. Rosseau next purchased a stand of timber with the intention of entering the lumber business, but the venture failed. This did not discourage him unduly; by the time he was thirty-five he owned an import brokerage business in New Orleans, LA, which provided him with enough income that he decided to go to France to study art, leaving the company in the hands of a partner.
Instead of taking a ship across the Atlantic, Rosseau headed West from California. On the ship from San Francisco, CA, to Honolulu he met Nancy Bidwell, on whom he kept a guardian's eye at the captain's request and to whom he became engaged before landfall. The two stayed in Hawaii as guests of friends made on board until Bidwell's vacation ended, at which point she returned home to Chicago, IL, and Rosseau went on to Japan and points West. After arriving in Paris, France, around 1894, he enrolled at the Académie Julian and soon thereafter married Bidwell, who had journeyed there to meet him. While there he studied under the painters Jules Lefebvre, Charles Herrmann-Léon, and Tony Robert-Fleury painting the nude figure, and winning an honorable mention for one of his paintings of this subject in 1900 at the Exposition Universelle in Paris. When his New Orleans import business partner emptied the company accounts and fled in 1898, it was Nancy's dowry that enabled the couple to stay in France so that Rosseau could continue his studies. Not having the patience to flatter a portrait sitter, he executed a picture of Diana with two wolfhounds, which met with critical acclaim in 1903. Rosseau's next exhibit was in 1904 at the Paris Salon, showing a painting of two setters which sold immediately. He exhibited again at the Salon in 1906 a life-size composition done from memory showing his own pack of fifteen and a half couple killing a panther in Texas, which won a third-class medal and launched his commercial career as a sporting and animal artist. Although he remained in France until 1915, Rosseau made numerous trips to the United States to exhibit and to fulfill orders for commissions, including his 1913 portrait of a pack of foxhounds belonging to Joseph B. Thomas, M.F.H, in full cry across Percy Rockefeller's Overhills plantation in Fayetteville, NC. When he was compelled by the onset of the First World War to return to the United States permanently, he settled in Lyme, CT, and took part in the Old Lyme artists' colony. He also spent time at the Southern estates and hunting grounds of his wealthy patrons, where he took part in upland game pursuits and executed commissions for them. Among these was Percy Rockefeller, who loaned Rosseau gun dogs for models and built a studio for the artist to use during the gunning and field trial season. In 1925 Rosseau was again commissioned by Joseph B. Thomas, this time to paint two large portraits of his pack of hounds, each of which were set at Overhills and depicts the pack working out a line in the foreground with huntsman, staff, and field in the background set among abandoned cotton fields and piney woodlands. Some of Rosseau's paintings were reproduced as photogravures; examples include his 1923 works Pointers in the Field and English Setters in the Field, published and remarqued by Arthur Ackermann and Son of New York City in 1925, and signed in pencil by the artist. Rosseau also executed etchings in the early 1930s, preparing and striking the plates in his own studio; these images were titled and signed by the artist in ink. Examples include: Cooling Off, Bill's Covey, and Partners. Brown & Bigelow, printers of advertising posters, prints, and calendars of St. Paul, MN, published reproductions of these three etchings.
Rosseau was a member of the Pennsylvania Academy of the Fine Arts in Philadelphia, the Lotos Club in New York City, and the Lyme Art Association. He exhibited at the Paris Salon, the Lyme Art Association, and prominent galleries in New York City and elsewhere. The Orlando (FL) Museum of Art, The Columbus (OH) Museum of Art, and the Pennsylvania Academy of the Fine Arts all have examples of his work. The University of Rochester (NY) Memorial Art Gallery has In the Woods; the Genessee Country Village & Museum in Mumford, NY, has Setter in an Open Field; the Hecksher Museum of Art in Huntington, NY, has his Beginning the Day: Pointer Dogs; the American Kennel Club Museum of the Dog in St. Louis, MO, has Setter in the Field; and the Columbus (OH) Museum of Art has Hunting Dogs.
Rosseau died in Fayetteville, NC, on 29 November 1937.