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With more than 20 years of experience practicing law in Oregon, Glenn’s practice focuses on trusts and estates matters, with a particular emphasis on the resolution of disputes, protective proceedings, and Medicaid planning.
As an experienced trial attorney, Glenn represents clients in complex trusts and estates matters, including will contests, disputed estate and trust proceedings, disputes regarding decedents’ retirement accounts, proceedings to modify trusts, fiduciary removal proceedings, contested guardianship and conservatorship matters, as well as claims of undue influence, incapacity, and breach of fiduciary duty.
Representative clients include:
Glenn’s practice also includes estate planning, probate, and trust administration matters, in addition to a limited number of adoption cases each year.
In 2025, Glenn joined Catalyst Law as Senior Counsel after serving as managing partner of his La Grande-based firm, Mammen and Null, since 2010. Glenn joined the firm, managed by former Union County District Attorney, Dale Mammen, after graduating from law school in 2004. Prior to practicing law, Glenn and his wife, Heather, operated the Sears Authorized Retail Dealer in Island City.
Glenn is the past Chair of the Grande Ronde Hospital Foundation, past President of the La Grande Rotary Club, and volunteers extensively within Union County, Oregon. He lives in La Grande with his wife, two daughters, and a charming hound.