She was born in
Girard, Kansas, the daughter of physician
Henry Winfield Haldeman and his wife
Alice. Alice was the sister of social activist
Jane Addams, with whom Marcet maintained a close relation until the end of the Addams's life. Marcet studied at the
Rockford Seminary for Young Ladies (
alma mater also of her aunt Jane) and then the Dearborn Seminary in Chicago, until the death of her father in 1905, followed by
Bryn Mawr College in Pennsylvania. While at Bryn Mawr she became one of the closest friends and confidantes of the poet
Marianne Moore. After three years she left the college to continue her stage acting, graduating from the
American Academy of Dramatic Arts in 1910. Between 1910 and 1915 she performed with the
Orpheum Players and other
stock companies in Newark, New York, Montreal, St. Louis and other cities, under the name Jean Marcet. Marcet's
father and
mother ran the Bank of Girard. When her mother Alice died in 1915, Marcet once again returned to her hometown, where she took over management of the bank. That same year she founded The Jolly Club in nearby
Radley, for the benefit of the many young immigrants (from numerous countries, but especially Italy) who had come to work in the area's mines. The Jolly Club provided English lessons, practical training and safe diversion. The following year she began to found other clubs as well, including one for younger boys and an Italian language club. These became quite popular and in 1921 she turned one of them into a school, where she taught. During her youth Marcet had spent many summers with her aunt, Jane Addams, at
Hull House; she credited Addams with much of her inspiration and over the years the two of them discussed Marcet's clubs both in person and through correspondence. In 1916 she married activist and publisher
Emanuel Julius. At her aunt Jane's suggestion, both partners adopted the surname Haldeman-Julius. They wrote both separately and together, their most well-known collaboration being the 1921 novel
Dust. "She travelled to the Soviet Union in 1931-1932 to report on the status of the Russian Revolution for
The American Freeman. […] In the 1930s she did numerous articles and short stories with John W. Gunn, a writer for the Haldeman-Julius press." In 1932 she was a delegate to the National Convention of the
Socialist Party of America and that same year Emanuel ran for Senate on the Socialist Party ticket. Marcet and Emanuel had two children, Alice (1917–1991) and Henry (1919–1990) and adopted a third, Josephine (b. 1910). "In 1933 the couple legally was separated but continued to live in the same house", though she "spent a lot of her time at the [Addams] family farm in
Cedarville." Marcet died of cancer in Girard in 1941 and is buried in Cedarville, Illinois. Her epitaph is a paraphrase of the one
W. K. Clifford wrote for himself: "I was not, and was conceived. I loved, and did a little work. I am not, and am content." Her papers are held at Kansas State University Libraries, Bryn Mawr,
Pittsburg State University, the University of Illinois at Chicago and Indiana University. See . ==Selected works==