During his nearly eight years as a prosecutor, Dennis handled serious violent felonies as well as White Collar Crimes. During his tenure, he was promoted to Senior Assistant District Attorney and was assigned to the Narcotics, Major Crimes, and Insurance Fraud Bureaus. In 2009, he left to establish his own criminal defense practice. Since 2009, Dennis has represented clients charged with homicide, attempted murder, and assault, as well as narcotics offenses and Driving While Intoxicated. He handles cases in federal and state courts in the five boroughs and Long Island.