When Montgomery moved to Los Angeles, she stayed with two of her brother's friends while sending a head shot every day to Julia Roberts' former manager, Bob Mc Gowan, until he signed her.She appeared in several small television roles through the late-1990s, including NYPD Blue.That same year, she began to star in the CBS police drama Unforgettable as Carrie Wells, a former homicide detective with hyperthymesia which allows her to have perfect recall, who is convinced to join the NYPD in Queens by her ex-boyfriend, after leaving Syracuse because of the investigation into her sister's murder being shut down.In late 2011, Montgomery began dating Shawn Sanford, director of lifestyle marketing for Microsoft, whom she met in Puerto Rico.
TV would prove a good fit for Montgomery, and she would find additional success with series like Without a Trace and Unforgettable.
In the series she portrays FBI agent Samantha Spade with marked believability.
As one season of Without a Trace after another unfolded, Montgomery worked with equal emphasis in film and television.
She later starred as Detective Carrie Wells on the police drama Unforgettable.
She dropped out of school at age fifteen to pursue acting on stage and emigrated from Australia to the United States when she was eighteen.