Lilleaasen has extensive experience working with contract and construction law, corporate law, finance and legal issues related to real estate. Through his work he has prepared a wide range of contracts (both in Norwegian and English). Lilleaasen also provides general advice and support in disputes concerning company law and general contract law.
| 2015- | Partner, Advokatfirmaet Føyen AS |
| 2007-2015 | Partner, Advokatfirmaet Torkildsen & Co AS |
| 2006-2007 | Senior Associate, Torkildsen, Tennøe & Co |
| 2001-2006 | Senior Associate, Advokatfirmaet Sørlie Wilhelmsen ANS |
| 1998-2001 | Christiania bank- og kreditkasse ASA (Nordea Norge Bank ASA) Legal section; associate, senior associate |
| 1993-1996 | Ministry of the Environment, International section; consultant |
| 1996 | Master of Law, University of Oslo |
