McGregor was born in 1983, and still resides in her native Vancouver. She has a sister. McGregor would like to work with Christopher Guest and considers Lucille Ball her favourite Comedian. She enjoys interviews, but hates auditioning.
In 1999, McGregor appeared in an episode of the Disney series So Weird as Gabe Crawford, the girlfriend of a lead character.
Also in 2002 she won the Women In Film And Video Vancouver Artistic Merit Award for Flower & Garnet and Bitten.
In 2005 she appeared in an episode of Supernatural as a preacher's daughter, and had a small part playing Keri Russell's sister in the Hallmark Hall of Fame drama The Magic of Ordinary Days.
In 2006 she portrayed Catherine Nyland, an archaeologist suffering from debilitating migraines in That Beautiful Somewhere, opposite Roy Dupuis. From 2005 to 2008 she had a recurring role as Alicia Plecas in the Canadian series Robson Arms, and in 2007 she appeared in American Venus as Jenna Lane, a competitive ice skater hovering on the brink of a mental breakdown due to her controlling mother (portrayed by Rebecca De Mornay).
Most recently, McGregor has had guest roles on The Listener, Almost Human, and FX’s Fargo.