Lowes was born in Queens, New York City. She graduated from New York University's Tisch School of the Arts with BFA in acting, and later was cast in the stage play Four Saints in Mexico. In 2004, Lowes landed her first screen role in the FX series Rescue Me and later co-starred opposite Marcia Gay Harden in the Showtime pilot, Hate. Lowes later guest starred in the number of television series, including The Sopranos, Without a Trace, NCIS, Ghost Whisperer, Castle, Leverage, and The Closer. In 2008 she starred opposite Laurie Metcalf in The CW short-lived comedy-drama series, Easy Money. In addition to her television performances, Lowes appeared in a number of low-budget films, including The Job (2009), Bear (2010), and Café (2011).
Lowes is best known for her role as Quinn Perkins, formerly Lindsay Dwyer, in the ABC political drama series Scandal created by Shonda Rhimes. Before Scandal, Lowes had guest roles on Shonda Rhimes' Grey's Anatomy and Private Practice. Before landing her breakout role on the show, she worked as nanny for Connie Britton's adopted son.
Lowes lives in Los Angeles with her husband, actor Adam Shapiro. Shapiro played her character's boyfriend in episode 12 (Season 2) of Scandal. With Shapiro, she is one of the founders and directors of the Los Angeles-based IAMA Theater Company, and a supporter of Southern California's black box theater community.