Of Counsel

Municipal & Public Entity Law
Business Law and Litigation
Education Law

O: (716) 854-3400 x229
F: (716) 332-0336

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Sean Costello is of Counsel to Rupp Baase, with a limited private law practice focused on municipal and public entity law.  He partners with his municipal and public entity clients and delivers high‑quality legal solutions, never forgetting that government entities must be trusted by those that they serve and must act responsibly toward their ratepayers or taxpayers.  Many legal rules apply only – or at least differently – to government entities, and Sean focuses on learning and applying these rules for his clients’ protection or advantage.  He believes that municipal entities deserve counsel that focuses on and understands their legal issues and challenges, not counsel that merely dabbles in the occasional municipal-law matter.

The broad array of legal matters that Sean has handled for municipal clients has allowed him to develop proficiency in matters as diverse as the investigation and litigation of tort claims, assisting with the procurement process, inter-municipal cooperation agreements, Union grievances and PERB charges, and the nuances of the Open Meetings Law.  Sean defends public entities in tort, civil rights, and employment-based claims in state and federal court.  He also serves as trusted counsel to help navigate the myriad of issues and challenging situations that happen only once, but can keep officials awake at night if they do not have a trusted legal advisor to serve as a guide.


Syracuse University, B.A. International Relations, magna cum laude

Syracuse University College of Law, J.D.


New York State

New Jersey

United States District Courts, for the Western, Northern and Southern Districts of New York

United States Bankruptcy Court, Western District of New York

United States Court of Appeals for the Second Circuit


New York State Bar Association

Erie County Bar Association


“30 Under Thirty,” Business First

New York State Academy of Trial Lawyers Excellence in Advocacy Award

2013 Erie County Bar Association Volunteer Lawyers Project:  Pro Bono Award in Unemployment Benefits Matters

District Award of Merit, Red Jacket District, Boy Scouts of America, 2015

Director’s Award, Saturn Players, 2016

Upstate New York Super Lawyers Rising Star, 2016 – 2019