For most of his career Mr. Neesemann prosecuted and defended complex business cases in court and in arbitration. Recognizing the significant savings and other benefits to clients from alternative dispute resolution (ADR) procedures such as arbitration and mediation, he came to focus his practice on acting as an advocate or as a neutral in the process of resolving cases. Since being diagnosed with Parkinson's Disease, he has concentrated on acting as an arbitrator or mediator in commercial cases. His cases have involved a broad spectrum of legal areas including breach of contract, intellectual property (patents, trademarks, unfair competition, trade secrets), employment, securities, insurance coverage and construction.

Mr. Neesemann is Co-Chair of the Arbitration and ADR Committee of the Commercial and Federal Litigation Section of the New York State Bar Association and Former Chair of the Arbitration Committees of the Association of the Bar of the City of New York and the Dispute Resolution Section of the American Bar Association. He is a member of the Panel of Commercial Arbitrators of the American Arbitration Association and of the Panel of Distinguished Neutrals of the CPR Institute for Dispute Resolution. He is a Fellow of the College of Commercial Arbitrators and a member of the Advisory Board for the Revised Uniform Arbitration Act of the National Conference of Commissioners on Uniform State Laws. He was also a member of CPR's Commission on the future of arbitration.

He helped found Parker Auspitz Neesemann & Delehanty in 1977, and joined Morrison & Foerster as a partner in 1987. Until 1993, he led the Litigation Group in Morrison & Foerster's New York office.