Å sa Larsson was born and grew up in Kiruna, Sweden. She is a qualified lawyer and made her debut in 2003 with The Savage Altar, which was awarded the Swedish Crime Writers' Association prize for best debut novel. Its sequel, The Blood Spilt, was chosen as Best Swedish Crime Novel of 2004, as was The Second Deadly Sin in 2011. Her novels were adapted for television and shown on More 4.
The sixth and final book in the Rebecka Martinsson series, The Sins of Our Fathers, was named Best Swedish Crime Novel of the Year, and is the winner of the Adlibris Suspense Award, the Storytel Award.