Mr. Sweeney focuses on inheritance law, particularly in the areas of wills, trusts, and estate planning. He also advises on elder law, tax law, business law, mergers and acquisitions, and international law. He comprehensively assists clients with strategic asset planning and complex business law matters.

He is a hands-on, business-minded lawyer who consistently works in a solution-oriented manner. He has extensive experience in creating tailored estate plans that are customized to each client's individual situation. This includes all forms of wills, trusts, and other estate planning instruments. His expertise also extends to designing complex estate structures involving different legal systems and international connections – including cross-border assets and legal issues. Furthermore, he advises on trust structures for tax planning, probate avoidance, and asset protection.

His tax expertise is broad, encompassing in-depth knowledge of U.S. and international tax law, particularly concerning Europe, Asia, and South America. Mr. Sweeney advises corporations, individuals, and organizations on cross-border taxation and the minimization or avoidance of double taxation. His experience in corporate management and mergers & acquisitions (M&A) is based on his work as an attorney, manager, and CFO in start-ups and growth companies, as well as in the insurance and financial services industries, shaping his distinctly business-oriented approach. He has worked for both privately held and publicly traded companies and possesses over ten years of international experience in Europe, South America, and Asia. His M&A experience includes over 30 transactions with a total value of approximately $12 billion, many of which had an international focus.

John's professional career includes, among other things, the position of Chief Financial Officer (CFO) of a publicly traded dot-com company and heading the tax department of an international insurance company with $6 billion in revenue. He also served as CFO, General Counsel, and Chief Compliance Officer of a private equity portfolio company. Prior to that, he was CFO of ING International Insurance Holdings, a complex multinational insurance company with over $4 billion in revenue. His previous roles included Tax Director at Aetna International and tax attorney at AIG's corporate headquarters.

John is a member of the bar associations of Connecticut, New York, and Washington, D.C.