Mathias was born in Eupen, Belgium in 1970.
After his primary school education in the German speaking region of Belgium, he completed his high school education and his candidature in law in the French speaking Belgian cities of Liège and Namur before graduating with a law degree from the Flemish speaking Catholic University of Louvain in 1994.
As part of his university studies Mathias participated in a one year Erasmus student exchange program at the University of East Anglia in Norwich in 1993/94 (which is where he first learnt how to speak English).
Following two visits to Perth in 1994 Mathias made the decision to migrate to Australia permanently, attracted by the great lifestyle and opportunities on offer in Western Australia.
With his Belgian law degree not readily recognised for practice in Perth, while getting himself organised, Mathias worked for a short time as a gardener at Presbyterian Ladies College in Perth.
During those first months in Perth Mathias became involved as a Liberal Party volunteer in the lead-up to the successful 1996 State election campaign.
Following that election Mathias worked as a Ministerial Chief of Staff and then a Senior Adviser to then Western Australian Premier Richard Court before taking on a role as an Adviser with the then Justice and Customs Minister Chris Ellison.
In 2001, realising a childhood dream, Mathias obtained his Private Pilots Licence through the Royal Aero Club of Western Australia.
Between 2003 and 2007 Mathias worked for major Western Australian health insurer HBF in a range of senior management roles, most recently as General Manager HealthGuard and, pending his appointment to the Senate, as Acting General Manager of HBF Health Insurance.
Having joined the Liberal party in Western Australia in 1996, Mathias was elected Senior Vice President of the Perth Division in 2000, State Vice President in 2003 and State Senior Vice President in 2004, a responsibility he fulfilled until March 2008.
Mathias is the Shadow Assistant Treasurer and Shadow Minister for Financial Services and Superannuation.
He is also the Chair of the Senate Select Committee on Fuel and Energy and has participated in a range of Senate Inquiries in 2008, including into Labor’s Workplace Relations (Transition to Forward with Fairness) Bill 2008, the Wheat Export Marketing Bill 2008, the Tax Laws Amendment (Medicare Levy Surcharge Thresholds) Bill 2008 and the Excise Legislation Amendment (Condensate) Bill 2008.
Mathias is married to Hayley, a lawyer with the Perth office of Clayton Utz.