McMein was one of 20 Society of Illustrators' artists to have their work published on a United States Postal Service Collectible Stamp sheet in 2001.

[2] John Baragwanath, her husband, stated that she chose the name Neysa after meeting one of Homer Davenport's fillies at his stables.

"[4] McMein made posters for French and United States governments during World War I, as did Thelma Cudlipp, Helen Hyde[7] and Mary Brewster Hazelton.

They are heralded by the blowing of sirens and the ringing of church bells, and amid this din the lights are extinguished and then suddenly come the bombs, falling no one knows where.

"[5] McMein made portraits of some of the soldiers, drew cartoons, and colored the design of the Indian head insignia that was then used by the 93rd Bomb Squadron to denote the number of German planes that a given plane shot down by drawing a German black cross over one of the bear teeth in a necklace worn around the Indian head.

[11] In 1917, noted poet Berton Braley wrote Front Page Stuff about her magazine cover art, the last portion of which is:[12] Yes, Neysa, we're strong for your stuff, Keep on for we can't get enough Your vogue is far more than a fad Nope, there is no charge for this ad —Berton Braley[12] Her illustrations appeared on the covers and within articles for McClure's magazine by 1919.

Within the covers of the magazine were illustrations made by the three artists to sell consumer products, like Orange Crush, Ivory soap, Chesterfield cigarettes, and Holeproof Hosiery.

[3][4] Together with artists Howard Chandler Christy and Harrison Fisher, McMein constituted the jury for Motion Picture Classic magazine's "Fame and Fortune" contest of 1921/1922, which discovered the It girl Clara Bow.

[21] The image of the "ageless" 32-year-old was used in advertising and on packaging until 1955 when Hilda Taylor painted an updated Betty, who also wore bright red and white clothing.

[22] Like the Betty Crocker image, "Miss McMein was herself a kind of American demigoddess: the most courted of commercial artists, hostess in her New York studio to all of the 'Algonquin wits'—Benchley, Parker, Franklin P. Adams—a wit herself.

McMein, while talented, was unfamiliar with comic strip drafting and conventions, and Guggenheim's writing suffered with the format.

[5] McMein entered the field of portraiture, at first using pastels to depict Dorothy Parker, Edna St. Vincent Millay, and Helen Hayes.

[18] She painted portraits of presidents Herbert Hoover and Warren G. Harding, author Anne Morrow Lindbergh, and actors Charlie Chaplin and Beatrice Lillie.

[3] McMein also painted Katharine Cornell,[25] Kay Francis,[26] Janet Flanner, Dorothy Thompson, Anatole France, Charles Evans Hughes and Count Ferdinand von Zeppelin.

[5] By 1920, McMein had walked in suffrage parades, traveled overseas extensively, and had ridden in Count Zeppelin's dirigible.

[1][27] McMein—described as a tall, athletic, grave, and beautiful red-head[e]—became a regular member of the Algonquin Round Table set,[29][4] formed after the end of the war.

[5] Her West 57th Street studio in New York City became an "outpost" to the Algonquin Hotel,[29][4] which appealed to the "Bohemian" nature of its members,[2] which included Dorothy Parker, Alexander Woollcott, Edna Ferber, Irving Berlin, Robert Sherwood, Franklin Pierce Adams, Robert Benchley, Alice Duer Miller, Harpo Marx, and Jascha Heifetz.

[4] The same year, McMein married John G. Baragwanath [Wikidata], a mining engineer and author,[4] whom she met at a party given by Irene Castle.

In his memoirs, the lyricist and publicist Howard Dietz recalled hearing that on one occasion, when Neysa noticed that her model for the day was impatient to leave, she asked: "Have you got a heavy date?"

'"[32] She also had affairs with Robert Benchley,[5] Charlie Chaplin,[2] who had a house near her cottage in Port Washington,[18] and a platonic relationship with Irving Berlin.

[2] This occurred during a period when "[w]omen are for the first time demanding to live the forbidden experience directly and draw conclusions on this basis," according to Beatrice Hinkle in an article for The Nation.

She interspersed her life as an artist with riding on the back of an elephant in a parade, taking a swim on a whim, and enjoying parties.

[35] The United States Post Office released a 20-stamp collection in February 2001 that are based upon works created by 20 Society of Illustrators' artists, including McMein, Rockwell Kent, Al Parker, Howard Pyle, Jessie Smith, and Joseph Leyendecker.