Constantine Gionis
Constantine Gionis cover
Constantine Gionis

Constantine Gionis

Principal Gionis Legal & Advisory

location
Sydney, NSW
Click to Reveal Phone Number(02) 801..

About Constantine

Constantine Gionis serves as the principal of Gionis Legal & Advisory Pty Ltd, a distinguished legal practice established as per the Legal Profession Act (NSW) 2004. Admitted as a solicitor in 1993, Constantine brings a wealth of experience in general commercial law, contracts and tendering, dispute resolution, and regulatory investigations and prosecutions. His expertise extends to Australian Consumer Law and governance and compliance, having received the Highly Commended Award for Excellence in Government Legal Services by the Government Solicitors’ Committee, Law Society of NSW. Constantine's academic background is robust, including a Bachelor of Arts in Economics and Political Science from the University of New South Wales, a Diploma of Law from the Legal Profession Admission Board, and a Master of Laws from the University of Sydney. He completed his Graduate Diploma of Legal Practice at the College of Law, NSW. His professional journey began at ASIC, where he honed his skills for six years before taking on significant roles such as Corporate Lawyer and Deputy Company Secretary at Thales Australia. Here, he addressed complex projects and tenders in defence and civil domains and managed corporate acquisitions and disposals. His tenure as Group General Counsel & Company Secretary at Cement Australia saw him advising on extensive legal and regulatory issues within the industry. In 2013, Constantine founded Gionis Legal & Advisory, where he leads in the establishment of new business ventures, corporate restructuring, and competition law advice. His proficiency in contracts, corporate governance, and compliance has made him a trusted advisor in sectors such as government, defence, manufacturing, and shipping. A fluent Greek speaker, Constantine also provides strategic guidance on management of regulatory investigations and commercial disputes. His leadership extends to mentoring junior lawyers and delivering legal and compliance training to non-legal executives.

Practice Areas

Commercial Law
Employment Law
Intellectual Property
Property Law

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Resume

Experience

Principal
Principal
Gionis Legal & Advisory
Sep 2013 - Present · 12 years 9 months
Consultant
Consultant
Meridian Lawyers
Jan 2013 - Aug 2013 · 7 months
Group General Counsel & Company Secretary
Group General Counsel & Company Secretary
Cement Australia
Aug 2007 - Sep 2012 · 5 years 1 month
Corporate Lawyer & Deputy Company Secretary
Corporate Lawyer & Deputy Company Secretary
Thales Australia
Jan 2000 - Aug 2007 · 7 years 7 months
Lawyer
Lawyer
ASIC
Jan 1994 - Jan 2000 · 6 years

Education

Master’s Degree, Law
Master’s Degree, Law
University of Sydney
1994 - 1997
Grad Dip, Practical Legal Training
Grad Dip, Practical Legal Training
College of Law
1993
Dip Law, Law
Dip Law, Law
Solicitors & Barristers Admission Board
1990 - 1993
BA, Economics & Political Science
BA, Economics & Political Science
UNSW
1987 - 1989

Awards

1970
Highly Commended Award Excellence Award for Government Legal Services
Government Solicitors’ Committee, Law Society of NSW

Contact Information

Sydney, NSW

LocationLevel 11, 65 York St, Sydney, NSW
Click to Reveal Phone Number+61 (2) ..
WebsiteView Website

Practice Certificate

Name
Constantine Gionis
Date of Admission
1993
Certification type
Principal of a law practice
Class
Law Practice
Region
NSW
CheckLast checked: 11 Jun 2026•
Checked with the Law Society of NSW

Practice Categories

Commercial Law
  • Company Secretarial
  • Farm Succession Planning
  • General Advice
  • Notary Public
  • Strata Law
  • Superannuation
  • Tax Law
  • Technology Law
  • Trusts
Employment Law
  • Disputes
  • Unfair Dismissal
  • Workers Compensation
Intellectual Property
  • Disputes
  • Patents and Trademarks
Property Law
  • Banking & Finance
  • Construction Law
  • Conveyancing
  • Leases
  • Mortgages