Treasurer Davis was first elected to the Maryland House of Delegates in 1994 at the age of 27, making him one of the youngest African-Americans ever elected to the Maryland General Assembly. He was appointed Chairman of the House Economic Matters Committee on January 8, 2003, becoming just the fourth African-American to chair a House standing committee and the first from Prince Georges County. This committee has wide-ranging responsibilities in the areas of banking, telecommunications, public utilities, insurance, science and technology, professional licenses, and alcoholic beverages. Delegate Davis has successfully sponsored legislation that lowered the states drunk driving threshold to .08, raised the states minimum wage above the national rate, increased financial assistance for low income residents to pay electric bills, and promoted education related to concussions and youth athletics. He has received numerous awards including the 2012 Mission of Love Founders Award, 2011 Maryland Clean Energy Centers Legislative Leadership Award, 2010 Maryland Black Caucus Foundations Outstanding Leadership Award, 2009 AOBA Outstanding leadership Award, 2007 American Heart Associations Public Official Award, 2006 Maryland Consumer Rights Coalitions Legislator of the Year Ward, and the 2002 Mothers Against Drunk Driving Award of Excellence.
Dereck and his wife, Monique, reside in Mitchellville with their two children, Dereck Jr. and Nyla. He is an active volunteer with the Marlboro Boys and Girls Club and the Foundation.