Most widely known for her impactful presence in the Broadway documentary, EVERY LITTLE STEP, this award winning triple threat performer has worked professionally since the age of nine. Born to the theatre family of Italian prima ballerina Anna Aragno and 2021 Kennedy Center Honoree Puerto Rican Opera singer Justino Diaz, Natascia grew up in New York City, beginning her training at The School Of American Ballet, going on to receive a BFA with Honors from Carnegie Mellon University.  After dancing the role of Anita with the New York City Ballet for their ‘West Side Story Suites’ helmed by Jerome Robbins, she became the last Anita ever to have been hand picked by both Jerome Robbins himself and librettist Aurthur Laurents to perform the role in the subsequent National tour of WEST SIDE STORY. Her breakout performance as Anita garnered Chicago’s Joseph Jefferson Award and St. Louis's Kevin Klein Award, and was met with critical acclaim across the country and internationally with headline reviews; "Diaz Shines In Soaring 'Story'" (Denver Post), "Show-Stealer Keeps Things Fresh in old 'Story' (Boston Tab), and ''Anita Makes A Star Out Of Diaz" (Boston Globe).  Her Broadway credits include the original Broadway companies and cast albums of Paul Simon’s THE CAPEMAN (Yolanda), SEUSSICAL (Bird Girl), and the 2004 revival of MAN OF LA MANCHA (Antonia), in which she also understudied the role of Aldonza, performing the role opposite Brian Stokes Mitchell. Off-Broadway credits include the role of Susan in the original run of tick, tick...BOOM! opposite New Kid On The Block Joey McIntyre, the original cast of Sondheim’s SATURDAY NIGHT, Esmeralda Agron the the Public Theatre's remount of THE CAPEMAN directed by Diane Paulus, JACQUES BREL IS ALIVE AND WELL AND LIVING IN PARIS (Helen Hayes Award, 2014), and Rafaela in the NY City Center Encores! production of GRAND HOTEL.  Her path in Washington DC theatre first began in the storied Sondheim Festival playing Petra in Sondheim's A LITTLE NIGHT MUSIC, and was later offered the titular role in KISS OF THE SPIDERWOMAN at Signature Theatre. At the 2009 Helen Hayes Awards, for her transformation into Scottish punk-rocker Monica P. Miller in the two-hander musical ROOMS at MetroStage, she cemented her presence in the D.C. theater community by winning her first Helen Hayes Award for Best Actress in A Musical in a tie with theatre legend, Chita Rivera. Her second Helen Hayes Award for Best Actress in A Musical came for her performance in MetroStage's production of JACQUES BREL IS ALIVE AND WELL AND LIVING IN PARIS, and in 2018, performing in Signature Theatre's production of Sondheim's PASSION, she took home her third Helen Hayes Award for her "obsessively watchable and gorgeously sung" (Washington Post) in a "career-defining performance" (BroadwayWorld) as Fosca. Other favorite roles include Jenny in THE THREEPENNY OPERA , which captured the headline of The Washington Post review; “At Signature, 'Threepenny Opera' s heart beats strongest with Natascia Diaz’s Jenny on stage”, Mariana in MEASURE FOR MEASURE, Savage in SAVAGE IN LIMBO, and originating the role of Betty #3 in the world premiere of COLLECTIVE RAGE by Jen Silverman at Woolly Mammoth Theatre.  Her television credits include Oz, Law & Order, SVU, The Jury, Nurse Jackie, Damages. She can be seen in her recurring role on FBI (CBS) as Detective Cantrell.