Reinders' Broadway debut was in The Adventures of Tom Sawyer as a swing and understudy for characters Amy Lawrence and Becky Thatcher. She next joined the 2002 Broadway revival of Into The Woods as an understudy for Cinderella, Little Red Riding Hood, Milky White, and Rapunzel. Her first starring role was in the 2003 revival of Gypsy as June; she went on to play Caroline in the 2005 jukebox musical Good Vibrations.

Reinders played the role of Glinda in the 2005 Chicago production of Wicked, alongside Ana Gasteyer as Elphaba; for this role, she received a Joseph Jefferson Award nomination for Best Actress in a Principal Role. She and Gasteyer finished their runs in the Chicago company on January 22, 2006. On May 30, 2006 she replaced Megan Hilty as Glinda in the Broadway production. While playing this role she performed "Popular" in a Daily Double about Wicked on an all-celebrity episode of Jeopardy!. TV personality Nancy Grace gave the correct question. She ended her run on January 7, 2007 along with former Chicago co-star, Ana Gasteyer.

Reinders was part of the cast in the show Party Come Here, which ran as part of the Williamstown Theatre Festival from July 25 through August 5, 2007. She appeared in the play The Fabulous Life of a Size Zero at the Off-Broadway DR2 Theater in 2007.

Reinders returned to the Gershwin Theatre on October 27, 2008 and took part in The Yellow Brick Road Not Taken, a selection of scenes and songs cut from early drafts of the musical Wicked.

Reinders was also a member of the band Tastiskank, along with Sarah Litzsinger. Reinders and Litzsinger co-starred opposite Constantine Maroulis in an independent TV pilot called Teachers. She also had a recurring role as a character named Ginger on the third season of the television series Ugly Betty. Reinders starred as a regular character, "Paula Morgan" on the Lifetime series Sherri starring former The View co-host Sherri Shepherd. The show premiered on October 5, 2009.

Reinders appears in the Mohegan Sun commercial, "Everyone's Invited" singing to the tune of the Rick James song Superfreak alongside former Wicked co-star, Saycon Sengbloh. She appears in the concert revue For The Record: Baz Luhrmann in Los Angeles, presented by ROCKLA for Show at Barre. It opened February 12, 2011, and closed June 30, 2011, with Jenna Leigh Green, Arielle Jacobs and Tracie Thoms. Reinders voices the character Jezebel in the video game Saints Row: Gat out of Hell.

Reinders originated the role of Portia in the Broadway musical comedy Something Rotten!, which opened April 22, 2015 at the St. James Theatre. Her last performance was on July 16, 2016.

Reinders married fellow actor Andrew Samonsky in May 2016. They were photographed by Photographers and Best Friends; Jacob & Krystle Robertson