In 1882, the entire Leyendecker family immigrated to Chicago, Illinois, where Elizabeth's brother Adam Ortseifen was vice-president of the McAvoy Brewing Company.

[3] After studying drawing and anatomy under John Vanderpoel at the Art Institute, J. C. and Frank enrolled in the Académie Julian[4] in Paris from October 1895 through June 1897.

They also shared a studio in Chicago's Fine Arts Building at 410 South Michigan Ave. J. C. Leyendecker had a long career that extended from the mid-1890s until his death in 1951.

[1][2][3] Upon his return from Paris in June 1897, Leyendecker illustrated for a range of mostly local clients including Hart, Schaffner & Marx, the Chicago department store Carson, Pirie & Scott, the Eastern Illinois Railroad, the Northern Pacific Railroad, Woman's Home Companion magazine, the stone cutter's trade journal Stone, Carter's monthly, the bird hobbyist magazine The Osprey, and books including Conan Doyle's Micah Clarke and Octave Thanet's A Book of True Lovers.

Eventually, his work would appear on 322 covers of the magazine, introducing many iconic visual images and traditions including the New Year's Baby, the pudgy red-garbed rendition of Santa Claus, flowers for Mother's Day, and firecrackers on the 4th of July.

He exhibited with and attended social events by the Palette and Chisel Club, the Art Students League, and the Chicago Society of Artists.

[7] After relocating to New York City in 1902, Leyendecker continued illustrating books, magazine covers and interiors, posters, and advertisements for a wide range increasingly prominent clients.

B. Kirschbaum,[7] Wick Fancy Hat Bands,[11] Gillette Safety Razors,[12] E. Howard & Co. watches, Ivory Soap, Williams Shaving Cream, Karo Corn Syrup, Kingsford's Corn Starch, Interwoven socks, B. Kuppenheimer & Co., Cooper Underwear, and Cluett Peabody & Company, maker of Arrow brand shirts and detachable shirt collars and cuffs.

Among the models were Brian Donlevy, Fredric March, Jack Mulhall, Neil Hamilton, Ralph Forbes, and Reed Howes.

As part of a major advertising campaign, he painted a series of twenty different images of children eating Kellogg's Corn Flakes.

In 1936, George Horace Lorimer, the famous editor at the Saturday Evening Post, retired and was replaced by Wesley Winans Stout (1937–1942) and then Ben Hibbs (1942–1962), both of whom rarely commissioned Leyendecker to illustrate covers.

[27] Due to his professional success, Leyendecker enjoyed a luxurious lifestyle with large home, domestic servants, and chauffeured car.

As the premier cover illustrator for the enormously popular Saturday Evening Post for much of the first half of the 20th century, Leyendecker's work both reflected and helped mold many of the visual aspects of the era's culture in America.

[29] The tradition of giving flowers as a gift on Mother's Day was started by Leyendecker's May 30, 1914 Saturday Evening Post cover[30] depicting a young bellhop carrying hyacinths.

In particular, the early work of Norman Rockwell for the Saturday Evening Post bears a strong superficial resemblance to that of Leyendecker.

The visual style of Leyendecker's art inspired the graphics in The Dagger of Amon Ra, a video game, as well as designs in Team Fortress 2, a first-person shooter for the PC, Xbox 360, and PlayStation 3.

[32] Leyendecker's Beat-up Boy, Football Hero, which appeared on the cover of The Saturday Evening Post on November 21, 1914, sold for $4.12 million on May 7, 2021.

[33][34] The previous world record for a J. C. Leyendecker original was set in December 2020, when Sotheby's sold his 1930 work Carousel Ride for $516,100.