At Wilson High School, she competed in track and field, hockey, and was involved in chorus, SADD, student council, and yearbook.

For all four years of high school, she participated in drama, and her yearbook states her plans were to attend a four-year college and major in theater.

While at DeSales, she performed in Act One's production of The Music Man as Marian Paroo and as the beggar woman in Sweeney Todd: The Demon Barber of Fleet Street.

[2] Roscioli was cast in the principal role of "Grizabella" in a national tour of Andrew Lloyd Webber's musical Cats from 2002 to 2003 and received critical acclaim for her performance.

[12] In late June 2010, Roscioli performed in a sold-out cabaret show Decidedly Dee at the jazz club Birdland.

She played the part of Mrs. Lovett in the award-winning musical Sweeney Todd: The Demon Barber of Fleet Street from June 13 to July 1, 2012.

[16] Roscioli participated in the workshop of the indie rock musical, Murder Ballad, presented by Vassar & New York Stage and Film's Powerhouse Theater.

[18] In 2017, Dee joined Paulo Szot at the Pennsylvania Shakespeare Festival's highly anticipated production of Evita which opened with record-breaking sales at the Labuda Center for the Performing Arts at DeSales University in Center Valley, PA. All 22 performances, from the previews June 14 &15, opening night June 16, thru July 2, were sold out.

[26] Roscioli reprised the role on the show's First National U.S. Tour, with performances from June 7, 2011 to October 2, 2011, replacing Jackie Burns.