Trey Mathisen was born and raised in Charleston and has a deep appreciation for his community and enjoys everything the Lowcountry offers. He is a graduate of Bishop England High School and earned a degree in Business Administration at The Citadel. Trey began his 30-year career as a licensed and certified real estate appraiser and agent. In 2004, he partnered to form the appraisal firm, Charleston Area Appraisals, specializing in residential properties along the South Carolina coast. From McClellanville to Edisto, his firm focused on historic homes, multi-unit properties, waterfront estates, resort communities and rural acreage.

Trey is one of the area's authorities by developers, builders, attorneys, agents and appraisers. His opinions are frequently sought as a consultant or expert witness, especially when it comes to complex properties and transactions. Trey has also acquired a vast knowledge of the construction and renovation process by working with contractors and investors. He understands the complexities involved with historic homes, major renovation and construction projects. Over the years, Trey has developed trusted relationships with local custom builders, full-service contractors, lenders and architects. His network of relationships create a seamless process when helping his clients buy and sell their Charleston homes.

Trey and his wife, Amy, have two children and have lived in I'On for more than twenty-five years. He was elected by his neighbors to serve on the I'On Homeowners' Association, last serving as vice-president of the board. He has also volunteered through the I'On Trust for neighborhood events and was awarded the Civitas Award in 2024 for his dedicated community service.

Trey has served as past president and board member of The Citadel Club of Charleston and volunteered with the Mount Pleasant Track Club. He is an active member of Grace Episcopal Church, serving in many volunteer capacities over the years. He is also a member of the Charleston Trident Association of Realtors and the National Association of Realtors.