He was next seen at North Shore Music Theatre in their 2002 production of "", where he starred as R.M. Renfield. He was then cast in the original production "Wicked" as a swing and then an understudy for Doctor Dillamond and The Wonderful Wizard of Oz in 2003. Then in 2004 he was in "The Irish Curse" at the Fringe Festival. In 2005 he starred in the original play "After the Night and the Music" at the Manhattan Theatre Club as Keith.  2006 saw Korbich in the original production of the musical "The Drowsy Chaperone" as George, earning him a Drama Desk Award nomination for best-featured actor. He would go on to be in the limited run of "The Most Happy Fella" at the State Theatre at Lincoln Center as the Doctor. ("Fella" was between The Ahmanson tryout and the Broadway run of "Drowsy".) He then appeared in the "Face the Music" revival in 2007 at the New York City Center. In 2008 he was the original Scuttle in the musical "The Little Mermaid". In the fall of 2010, Korbich performed at the La Jolla Playhouse in San Diego, California in the world premiere of "", a musical detailing the life of Charlie Chaplin. In February 2011 he was Gus/Growltiger and Bustopher Jones in "Cats" at Musical Theatre West in Long Beach, California. In 2012, Korbich appeared in the original Broadway cast of "A Christmas Story", appearing as Santa Claus and the Doctor. In 2013, Korbich was in the Emilia Clarke-led Broadway production of "Breakfast at Tiffany's". Later that year, Korbich was in the original cast of a "A Gentleman's Guide to Love and Murder".