[3][4] Invited to return to Australia to appear in Mame as the nephew Patrick to Rhonda Burchmore's Mame, he then played the part of Tony opposite Esther Hannaford in The Boyfriend,[17] before being cast by director Simon Phillips to play the groom Robert in Melbourne Theatre Company's production of The Drowsy Chaperone,[18] alongside Geoffrey Rush, Christie Whelan Browne, Robyn Nevin, Shane Jacobson, Rhonda Burchmore, Grant Piro and Rohan Browne.

First, Australian stage legend Nancye Hayes and musical director John Foreman cast Rathgeber in the part of Greg Connell in The Boy From Oz, in which he sang the classic I Honestly Love You to Todd McKenney's Peter Allen.

[22] During the Melbourne summer season of The Boy From Oz, artistic director Ken Mackenzie-Forbes invited Rathgeber to appear in the role of Billy Crocker in Anything Goes, teaming him up with Amanda Harrison as Reno, Wayne Scott Kermond as Moonface and Todd McKenney as Evelyn.

The stage adaptation of the film was co-penned by producer Sharleen Cooper Cohen and original screenplay writer Douglas Day Stuart, with music by Ken Hirsch, it also starred Bert Labonte, Kate Kendall, Amanda Harrison and Zahra Newman.

[25] For the Midsumma Festival of 2013, Dean Bryant created the verbatim play Gaybies, casting Rathgeber in a lineup including Magda Szubanski, Virginia Gay, Brent Hill and Trevor Ashley among others.

[26] In 2015 Rathgeber joined the cast of Next To Normal at Sydney's Hayes Theatre, playing the two doctor roles to Natalie O’Donnell's portrayal of mentally-ill Diana.

[28] The Australian tour of Anything Goes opened at the Sydney Opera House in September 2015[29] then travelled to the Princess Theatre Melbourne[30] and Queensland Performing Arts Centre, Brisbane.

[31] The production was directed by Dean Bryant and choreographed by Andrew Hallsworth, this time with Caroline O'Connor as Reno, Claire Lyon as Hope and Carmen Duncan as Mrs.

[33] Stepping straight off the Sydney Opera House stage, Rathgeber played the villain Carl in the Australian tour of Ghost the Musical opposite Wicked stars Rob Mills and Jemma Rix as Sam and Molly.

Sydney,[41] Light The Night,[42] The Brian Stacey Night,[43] the Save La Mama Theatre (Melbourne) concert, TheatreAid Flood Relief,[44] Black Saturday bushfires appeals,[45] and a regular guest singer for Very Special Kids' annual Memorial Day ceremonies[46] commemorating the lives of children who've lost their battle with terminal illnesses.

Rathgeber has headlined numerous concerts alongside the likes of Rhonda Burchmore, Matt Hetherington, Rob Mills, Lucy Durack, Tim Draxl, Chelsea Plumley, Marina Prior, James Millar, Elise McCann, Anna O'Byrne, Amy Lehpamer, Judi Connelli, Trevor Ashley, Gorgi Coghlan, Wendy Stapleton, Suzanne Johnston, Mathew Frank, Simon Burke and many more.

In 2004, Rathgeber made his solo cabaret debut with A Momentary Act at The Butterfly Club in Melbourne, directed by Martin Croft and featuring original music and accompaniment by composer-lyricist Matthew Lee Robinson.