Sharon G. Flake was born on December 24, 1955, in Northern Philadelphia, Pennsylvania. Flake grew up in a tight-knit family with six children. Flake's mother scrubbed floors for a living, and her father worked for Philidelphia Gas Works, having moved to Philadelphia after experiencing Jim Crow prejudices in the South. Flake attended the University of Pittsburgh at just seventeen years old, majoring in medicine. After taking several medical classes, Flake switched her major three times before becoming an English major. 

Post-graduation, a writing insecurity from early in life remained, particularly about her grammar and spelling, so she decided to work in a social services agency. After spending eight years as a houseparent helping youth in foster care, Flake was hired by the University of Pittsburgh Press’ Public Relations department. She was the Director of Public Relations for the University of Pittsburgh's business school by the time she turned thirty years old. However, Flake’s friends, who were also interested in writing, and her faith called her back to writing time and time again. For fifteen years, while working full-time in this position, Flake submitted short stories and articles to publishers, each of which was rejected. 

Nevertheless, Flake’s manuscripts were later signed by the very first publisher she sent them to, Andrea Davis Pinkney, after being picked out of the “slush” pile of new manuscripts. Her first work was The Skin I’m In in 1998, a book inspired by her daughter Brittney. This book, awarded the Coretta Scott King Award in 1999, is still widely celebrated as giving voice to common adolescent struggles with self-image. Flake continued to create stories about realistic characters, typically African American adolescents, using colloquial language. Flake's books have become extremely popular with middle- and high-school students. Her ability to relate to and understand the adolescent culture, while embedding wisdom about the possibilities of a better future, make Flake one of the most popular youth authors. 

Other works by Flake include Pinned (2012), a romance novel focusing on two characters, Adonis and Autumn, struggling to live as teenagers with disabilities. Flake has also published work in the Fresh Ink anthology (2018) focusing on African American experiences of adolescence, as well as in an anthology titled We Rise, We Resist, We Raise Our Voices (2018), which grapples with its contemporary political climate and the need to build a better future. 

Sharon G. Flake often visits schools and public libraries throughout the northeast, talking with adolescents about her past and the possibility of their future, letting them know that they "don't have to be perfect to do something [they] want to do." Her honest and hopeful approach appeals to adolescents in their stage of uncertainty and self-doubt. Flake continues to write and expand her advocacy for the trials and tribulations of inner-city youth. She lives in Pittsburgh at the time of this writing with her daughter, Brittney.