Hemphill grew up in Chicago and began writing at an early age, as part of the Young Authors afterschool program. Hemphill published poetry for adults first, but had always wanted to write for children. Eventually, she took a class at the University of California Los Angeles (UCLA) about writing children's poetry and the class inspired her to write her first novel.
Hemphill's first novel, Things Left Unsaid: A Novel in Poems (2005), is realistic fiction about a friendship between two girls which alternates between toxic and healthy. The characterization of the main characters was considered excellent and the pacing of the story praised by School Library Journal. The way that Hemphill writes Things Left Unsaid, according to Sara K. Day, allows the reader to become a confidante of the narrator, as if the reader is a friend, too. Things Left Unsaid won the Myra Cohn Livingston Award in 2006.
Hemphill won a 2008 Printz Honor for her book, Your Own, Sylvia, a novel in verse about the poet, Sylvia Plath. In working on Your Own, Sylvia, Hemphill shared that this novel faced many challenges, one of which was surviving the "censoring gauntlet of the Plath estate," but that she enjoyed writing about her because she loved Plath as an artist. Hemphill also felt a kinship to Plath during the time of her writing, since her marriage was ending and she was in the grips of being both overworked and depressed. She also worked in a manner similar to Plath, writing poetry every day, journaling and also writing to her mother, as Plath often did. The Chicago Tribune reviewed Your Own, Syliva, writing about the novel that "rarely is there such a striking and successful blend of literary form and subject." Your Own, Sylvia also won the Myra Cohn Livingston Award in 2008.
Hemphill's 2010 novel, Wicked Girls, is a free-verse historical novel of the Salem Witch Trials. Wicked Girls was a 2010 L.A. Times Book Prize Finalist. The Horn Book Magazine has singled out her novels in verse to highlight, calling the poetry in her 2012 work, Sisters of Glass, "elegant." In 2013 she wrote, Hideous Love, which is also written in free-verse is about the writer Mary Shelley. Hideous Love was considered by to be faithful to the history of Shelley's life, especially in imagining the difficulties of living under the principals of free love and "the compromises culture required of a woman of genius during the time period."
- "5Q Poet Interview Series: Stephanie Hemphill". Poetry for Children. 11 April 2012. Retrieved 18 August 2015.
- Morris, Ellen Birkett (20 August 2007). "Biographer Stephani Hemphill Digs Deep for Sylvia Plath's Emotional Truths". Authorlink. Retrieved 18 August 2015.
- Korbeck, Sharon (February 2005). "Things Left Unsaid: A Novel in Poems". School Library Journal. 51 (2): 136–137. Retrieved 18 August 2015. (Subscription required (help)).
- Day, Sara K. (2013). Reading Like a Girl: Narrative Intimacy in Contemporary American Young Adult Literature. Jackson, Mississippi: University Press of Mississippi. pp. 35, 45–50. ISBN 9781621039600.
- "Myra Cohn Livingston Award". Children's Literature Council of Southern California. Retrieved 18 August 2015.
- "Biography: Stephanie Hemphill". Teen Reads. The Book Report, Inc. Retrieved 18 August 2015.
- "2008 Michael L. Printz Award". Young Adult Library Services Association. The American Library Association. 2008. Retrieved 18 August 2015.
- "Your On, Sylvia: A Verse Portrait of Sylvia Plath". Kirkus Reviews. 75 (23): 9. 9 December 2007. Retrieved 18 August 2015. (Subscription required (help)).
- Hemphill, Stephanie (2008). "Printz Award Honor Speech". Young Adult Library Services. 7 (1): 8–9. Retrieved 18 August 2015.
- "Stephanie Hemphill". Baker & Taylor Author Biographies. 3 January 2000. Retrieved 18 August 2015. (Subscription required (help)).
- Russell, Mary Harris (6 May 2007). "For Young Readers". Chicago Tribune. Retrieved 18 August 2015.
- Cocoran, Jill (18 October 2008). "Celebrating Stephanie Hemphill & Poetry!". Jill Corcoran Books. Retrieved 18 August 2015.
- Smant, Lisa (7 September 2010). "Books With Mix of Fact, Fiction May Have Young Readers Wanting MOre". Star-Telegram. Retrieved 18 August 2015.
- "Books, Authors and All Things Bookish". Los Angeles Times. 22 February 2011. Retrieved 18 August 2015.
- Hedeen, Katrina (March 2013). "Novels in Verse". Horn Book Magazine. 89 (2): 143–144. Retrieved 18 August 2015. (Subscription required (help)).
- Nolan, Abby McGanney (8 October 2013). "Hideous Love: The Story of the Girl Who Wrote 'Frankenstein,' by Stephanie Hemphill". The Washington Post. Retrieved 18 August 2015.
- Coats, Karen (November 2013). "Hideous Love: The Story of the Girl Who Wrote Frankenstein". Bulletin of the Center for Children's Books. 67 (3): 156–157. doi:10.1353/bcc.2013.0836. Retrieved 18 August 2015. (Subscription required (help)).
- Sorby, Angela; Thomas Jr., Joseph T. (September 2008). "The 2008 Lion and the Unicorn Award for Excellence in North American Poetry". The Lion and the Unicorn. 32 (3): 344–356. doi:10.1353/uni.0.0409. Retrieved 18 August 2015.