She has said that "being a black and Native kid in Fort Worth in the '70s and '80s was pretty limiting"; thus, she turned to reading and writing, especially science fiction, as a form of escape.

Her father was an economics professor, and her mother was a high school English teacher who encouraged Rebecca's early attempts at writing stories.

One of her aunts, a former nun, later told her, “It would be better if you went away.”"[7] Roanhorse has said that she is of Ohkay Owingeh Pueblo descent through her mother's family, and African American on her father's side.

[1] Dr. Matthew Martinez, former Lieutenant Governor of Ohkay Owingeh,[8][9] welcomed Roanhorse on her first and only visit to the community, in 2018, and spent time with her.

"[1] Martinez continued, "by not engaging in any form of cultural and community acknowledgement, Roanhorse has failed to establish any legitimate claim to call herself Ohkay Owingeh."

Roanhorse told The New York Times that she initially worked on "Tolkien knockoffs about white farm boys going on journeys", because she figured that is what readers wanted.

[21] For example, the Saad Bee Hózhǫ́ writers' collective criticized the hero's use of bullets filled with corn pollen to slay the monster, which they viewed as a violent, disrespectful misuse of sacred ceremonial traditions.

[7] When asked in a Reddit AMA about including Navajo cultural aspects into her works, Roanhorse said her goal was "accuracy and respect" and gave examples of what she fictionalized and what she considered off-limits.

[10] In addition, Roanhorse sought Navajo views and input during the writing of Trail of Lightning, including PhD student Charlie Scott.

"[7] Prominent Native scholar Debbie Reese (Nambé Pueblo) initially praised Trail of Lightning, but upon hearing from Diné writers, poets and academics, she changed her mind about the book, writing that she'd "come to understand that Roanhorse had crossed the Diné's 'lines of disclosure,' an offense that many white interlopers had committed in the past.