Xavier attended St. Francis Xavier's College in Liverpool, Knutsford High School in Cheshire, and ultimately completed his professional acting training at the Manchester Metropolitan University in 1999. His first professional role was in the musical comedy Pageant at London's Vaudeville Theatre in 2000.

In addition, Xavier has worked as a recording Artist, with both radio and original Soundtrack credits to his name. In 2007, BBC Radio 2 presented a special edition of Friday Night is Music Night, celebrating the work of Leonard Bernstein and the 50th anniversary of West Side Story. Paul Gambaccini presented the program at London's Mermaid Theatre, featuring the BBC Concert Orchestra and Xavier as Tony. He also played Artie Green in the BBC Radio 2 live recording of Sunset Boulevard, performed at the Cork Opera House with Michael Ball and Petula Clark. Outside of radio, his work in recordings includes Bumblescratch (2016 London Concert Cast Recording) Collaborations: The Songs of Elliot Davis (2013), Lift (2012 Concept Album), Soho Cinders (2011 Concert Cast), Love Story (2011 Original London Cast), and Little Women (2004 Studio Cast).

In 2008, Xavier played Rock Hudson in Tim Fountain's play Rock at the Unity Theatre in Liverpool, the Library Theatre in Manchester, and the Oval House Theatre in London. It went on to be produced as a radio play by production company Made in Manchester, and won the Best Online Only Audio Drama award at the BBC Audio Drama Awards in 2012.

Xavier has been nominated twice for a Laurence Olivier Award. He was first nominated for Best Performance in a Supporting Role in a Musical in 2011 for his performance as Cinderella's Prince/Wolf in Into The Woods at the Regent's Park Open Air Theatre. The same year he was also nominated for the Best Actor in a Musical for his performance as Oliver in the musical Love Story at the Duchess Theatre. In January 2017, Xavier's lead performance in "Sunset Boulevard" (at the London Coliseum) won the 2016 BroadwayWorld UK/West End Award for Best Actor in a New Production of a Musical.

In 2013, Xavier co-presented the Olivier Awards BBC Radio 2 Covent Garden Stage with Claudia Winkleman, and returned again in 2014 to co-present on the ITV Stage with Myleene Klass. He also hosted the UK Theatre Awards at the historic Guildhall in the City of London in both 2013 and 2014.

Xavier's film work includes his portrayal of Tom in the 2014 production Never Let Go with Director Howard J Ford for Latitude Films, scheduled for release in 2015. In 2013, he appeared as Rob in the short film Gnomeland by writer/director Francesca Jaynes, as well as playing a Russian Gulag Prisoner in Walt Disney Pictures' Muppets Most Wanted, filmed at Pinewood Studios.

Xavier is the Principal of Musical Theatre Masterclass, a training school for musical theatre students which aims to aid them in gaining acceptance to professional training colleges. The school runs every Sunday, based at the Umbrella Rooms in the West End. Teachers include Anna Tringham (Head of Acting), Ross Sharkey (Head of Singing), Lucinda Lawrence (Head of Dance) and Lucas James (Dance Assistant). Students are also taught by performers and practitioners including Kerry Ellis, Ramin Karimloo, Rebecca Trehearn, Marc Antolin, Robbie Sherman, Katie Brayben and Matt Henry. The students are often given an opportunity to perform at various charity and West End events at which Xavier also appears. The students also appear at a Christmas concert at St Paul's, Covent Garden, alongside industry professionals. The 2016 concert was hosted by Rufus Hound.