Dennis has a diversified background in taxation and accounting, and has been specializing in tax services since 1993. His clients include individuals, manufacturers, wholesalers, professional service firms, and publishers.

His career at Citrin Cooperman began in 1997, when Robbins Greene Horowitz Lester & Company joined the firm.

Dennis is a graduate of Binghamton University. He is a member of the American Institute of CPAs and the New York State Society of CPAs.