Mary Susan Leahy

Mary Susan Leahy is an estate planning lawyer and senior counsel in McLane Middleton’s Trusts & Estates Department, working from Portsmouth and Concord, New Hampshire. She advises clients on personal estate and tax planning and business succession matters, drawing on prior experience as a transactional business lawyer. She also counsels families on generational planning involving lakefront and other vacation properties. Her practice includes professional trustee service and advice to charitable foundations and other tax-exempt organizations on planning and administration issues.

Susan earned an A.B. in Economics from Mount Holyoke College in 1966 and a J.D. from Boston University School of Law in 1970. Her legal education supports a long career spanning estate planning, taxation, corporate business law, real estate, trusts, and fiduciary work. She is a Fellow of the American College of Trust and Estate Counsel. Her admissions include New Hampshire and Maine state courts together with federal appellate, district, tax, and Supreme Court admissions, reflecting broad experience with the legal structures that affect trusts, estates, taxes, and business succession.

Susan’s areas of focus include corporate business law, estate planning, trust and estate administration, probate litigation, and taxation. She serves as a professional trustee for private trusts and advises charitable foundations and tax-exempt organizations. Her prior work in transactional business and real estate law informs succession planning and family property arrangements. This combination helps clients address estate plans that involve business ownership, valuable real property, fiduciary administration, charitable goals, and tax considerations across generations.

Mary Susan Leahy has received extensive professional recognition for corporate and trusts and estates work, including long-standing listings in The Best Lawyers in America. Her professional service includes bar organizations focused on elder law, taxation, real property, and probate. She has also contributed to civic organizations and pro bono service. Her practice brings together estate planning, tax knowledge, business experience, and fiduciary judgment to help individuals, families, trustees, and nonprofit organizations manage complex long-term planning needs.

Law Office Affiliations

• Attorney, McLane Middleton
• Member, New Hampshire Bar Association
• Member, Maine State Bar Association
• Member, New Hampshire Bar Association and Its Sections of Elder Law and Real Property and Probate
• Member, Maine Bar Association – Katahdin Counsel (Recognizing Pro Bono Civil Representation)
• Member, American Bar Association and Its Sections of Taxation and Real Property and Probate
• Member, New Hampshire Women’s Bar Association
• Founder and Chair of Its Board of Trustees, NH Civics
• Trustee, Holbrook Community Foundation

Licensed State

• New Hampshire
• Maine

Education

• Boston University School of Law
  Juris Doctor (JD)

Awards & Badges