In 1978 Dennis cofounded Design Collective and remains its CEO Emeritus and Chairman of the Firm’s Board of Directors. During his tenure as President the firm has grown to become one of Maryland’s largest and most successful architectural practices. Design Collective’s success can be attributed to Dennis’ leadership as well as the efforts of over 75 University of Maryland graduates, some of whom have advanced to become partners in the firm. Dennis continues to be active in local charities and is on the board of directors of the Community Foundation of Howard County. He also continues to support the University and the School of Architecture through an endowment and scholarship program. One of his individual honors includes the University of Maryland Distinguished Alumni Award.