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About Us

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Owen Costello

Founder & Owner

Owen moved to Charleston and began his career in real estate in 2019. After years of experience owning and operating several Jimmy John's franchises, Owen made the move to Charleston to be closer to his now wife, Madison. His experience on the front lines of the food and beverage industry, combined with the struggles of operating a business, gave him all of the necessary skills to thrive in a career in real estate. 


Known for his passion and energy-filled personality, Owen immediately became a Charleston multi-million dollar producer and has helped hundreds of families throughout the Charleston area buy or sell their most valuable asset. However, Owen quickly became aware of what was missing in the real estate industry - a truly service-based system. Too often we hear 'horror stories' about home sales gone horribly wrong. 


Owen founded Costello & Co with one word in mind: Freedom. He gives all of his clients the freedom to prioritize their own unique goals or needs. Too often home buyers and sellers are steered in a direction by their agent. They do whatever their agent tells them to do. In the end, the only people really impacted by a 'nightmare deal' are the clients themselves - not the agent! Owen wanted to put an end to this narrative - enter Costello & Co.

He has turned his love of and experience in real estate into a full-service system that helps buyers and sellers take control of their home sale so they can accomplish their own unique goals.

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Matt Marks

Realtor & Partner

Matt Marks joined Keller Williams after a distinguished 25 year career in business sales and sales management. Matt built his success around the philosophy that great business is done when you identify your client's needs and invest time in creating a customized plan that achieves their unique set of goals. This high level of service and client focused approach builds partnerships focused on achieving each client's specific needs.


Matt s commitment to customer and client satisfaction incorporates innovative strategy, problem solving and negotiating techniques that exceed clients expectations and establish long lasting relationships. Thinking outside of the box is a specialty that Matt is known for among family, friends, colleagues and clients. He has incorporated that focus and experience to his career in real estate.


A native of New England and longtime resident of the DC/Metro area, Matt and his family (and extended family!) moved to the Charleston area several years ago and they continue to grow deep community roots here in the low country. Matt lives in Mount Pleasant with his wife and three children and they spend time fishing on the Wando River and enjoying the Charleston area beaches and waterways.


Why Choose Me As Your Agent? When you work with me, you will receive a knowledgeable and professional real estate agent, a committed ally to negotiate on your behalf, the systems in place to streamline buying your home and the backing of a trusted company, Keller Williams Realty.

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