Erbe was born in Newton, Massachusetts, and raised in Weston, Connecticut. She began acting in high school and attended Northwestern University, where she majored in theater.
After graduating from college, Erbe moved to New York City and began appearing in off-Broadway productions. She made her Broadway debut in 1991 in the play "The Speed of Darkness".
Erbe's television career began in the early 1990s with guest roles on shows such as "L.A. Law" and "NYPD Blue". She had a recurring role on the series "Homicide: Life on the Street" from 1993 to 1995.
In 2001, Erbe landed the role of Detective Alexandra Eames in the NBC legal drama Law & Order: Criminal Intent. She played the role for ten seasons, until the show's cancellation in 2011.
Erbe has also appeared in several films, including "The Talented Mr. Ripley" (1999), "The Caveman's Valentine" (2001), and "What Doesn't Kill You" (2008).
In 2015, Erbe returned to television in the HBO drama series "The Leftovers". She played the role of Meg Abbott, a woman who has lost her family in the unexplained disappearances of millions of people.
Erbe is married to actor Terry Kinney. They have two daughters, Maeve and Carson.