After graduating from university, she worked for several years in publishing as an editor at Ray, Cawaii!, and other lifestyle magazines. In 1996 she quit her job to spend a year in the United States, and upon her return to Japan in 1997 she began a new career as a freelance writer.
While Nakajima worked on projects for clients, she was also working on several fiction manuscripts of her own. Her debut novel Futon, which refers to work of the same name by Katai Tayama, was published in 2003 and immediately nominated for the 2003 Noma Literary New Face Prize, but did not win. Around the time that Futon was published, Nakajima's father was diagnosed with dementia. For over a decade, until his death in 2013, Nakajima helped take care of her father while producing her novels and essays. She later drew on this experience to write her 2015 novel Nagai owakare (The Long Goodbye).
Nakajima followed Futon with two more novels and six short story collections, and in 2009 she received a grant from the University of Iowa Center for Asian and Pacific Studies to support a residency at the International Writing Program. In 2010 her novel Chiisai ouchi (The Little House) received the 143rd Naoki Prize, one of Japan's highest literary honors. Subsequent work received several more awards. Tsuma ga shiitake datta koro (When My Wife was a Shiitake) won the 42nd Izumi Kyōka Prize for Literature in 2014.Katazuno (One-Horn) won both the 2015 Shibata Renzaburo Prize and the 2015 Kawai Hayao Story Prize, while Nagai owakare (The Long Goodbye) won the 2015 Chuo Koron Literary Prize. In 2017 Darf Publishers acquired the rights to the English translation of Chiisai ouchi (The Little House), which will be published in 2018.
Nakajima bases many of her settings and characters on her own personal experiences, such as caring for a parent with dementia, as in Nagai owakare, or dealing with a youthful sibling, as in Kirihatake no endan. Ian McDonald, one of Nakajima's English translators, describes her writing as "deceptively simple prose."
2010 143rd Naoki Prize (2010上) for Chiisai ouchi (The Little House)
↑ Heitzman, Kendall (June 3, 2016). "Chapter 20: The Rise of Women Writers, The Heisei I-Novel, and the Contemporary Bundan". In Rachael, Hutchinson; Morton, Leith Douglas. Routledge Handbook of Modern Japanese Literature. Routledge. pp.285–298. ISBN9781317647720.