The former Grey's Anatomy actress will play one of the main roles in the project from Office producer Justin Spitzer, says The Hollywood Reporter.
The multi-camera ensemble sitcom follows a group of friends whose lives are changed after surviving a plane crash.
Leigh will play a character named Leah, who is described as an "irresponsible and absent-minded slacker", who struggles to progress in life despite her wit and intelligence.
The character has taken on several dead-end jobs and shares a ground floor flat in Minneapolis with her two best friends, Griffin and Sabrina.
Justin Spitzer will executive produce the series, along with Peter Traugott and Rachel Kaplan.
Coincidentally, Leigh exited Grey's Anatomy after her character Lexie Grey was killed in a plane crash.
The actress explained last year that she had decided to leave the ABC drama months before her character was killed off.