Hagen is experienced in real property, equity, bankruptcy and insolvency. His practice has expanded to briefs for administrative, international and constitutional law.
He regularly appears led and unled in the Supreme Court of New South Wales, the Administrative Appeals Tribunal, the NSW Civil and Administrative Tribunal, and the Federal Court of Australia. He also accepts briefs from Legal Aid New South Wales.
Hagen holds a Master of Laws and a Bachelor of Economics from the University of Sydney. He holds a Bachelor of Laws with Honours from the University of New South Wales.
Prior to being called to the Bar, Hagen practised as a solicitor in insolvency at Blake Dawson, now Ashurst, and was tipstaff to the Honourable Justice George Palmer AM QC.
Toyota Finance Australia Ltd v Gardiner  NSWCA 162
Capolingua v Da Silva  NSWSC 1212
Arambasic v Veza (No. 4)  NSWSC 1109
Burns v Corbett; Gaynor v Burns  NSWCA 3