Maxwell made her Broadway debut as an understudy in the Cy Coleman – David Zippel musical City of Angels in 1989.

[7][8][9] She then starred opposite John Ritter and Henry Winkler in Neil Simon's The Dinner Party in 2000 and in Sixteen Wounded in 2004 with Judd Hirsch and Martha Plimpton.

[13] In 2006, she starred in Roundabout Theatre Company's Off-Broadway revival of Joe Orton's Entertaining Mr. Sloane for which she received a Drama Desk nomination for Best Actress.

[21] In 2008 she appeared Off-Broadway with the Potomac Theatre Project/NYC in Howard Barker's Scenes from an Execution and was nominated for a Drama Desk and NYITT award.

[26] Maxwell starred as Maria in the Broadway revival of Lend Me a Tenor, which began performances at the Music Box Theatre on March 11, 2010.

[31][32] Maxwell played the role of Phyllis Rogers Stone in the Kennedy Center production of the Stephen Sondheim–James Goldman musical Follies, running from May 7 to June 19, 2011, at the Eisenhower Theater in Washington, DC.

[35] She appeared in the PTP/NYC (The Potomac Theatre Project) Off-Broadway production of the Howard Barker play Victory: Choices in Reaction, in a limited engagement in July 2011.

[37] She appeared in the Off-Broadway production of the Anthony Giardina play, The City of Conversation at the Lincoln Center Mitzi Newhouse Theater, from May 5, 2014, to July 26, 2014.

[38][39] In an interview with Time Out New York in July 2016, Maxwell announced that she was retiring from theatre after the run of her second production of Scenes from an Execution then in rehearsal.

[40] She was also a voice actress and read several audio books, including Mary Higgins Clark's Two Little Girls in Blue[41] and No Place Like Home.

[42] Maxwell starred as a "scheming Senator" in the CBS TV series BrainDead alongside Mary Elizabeth Winstead, Aaron Tveit and Tony Shalhoub, which aired from June to September 2016.