He was previously a Democratic member of the Maryland Senate from the 26th district in Prince George's County.

He attended Johnson C. Smith University in Charlotte, North Carolina, where he earned a Bachelor of Science degree in biology in 1965, and the University of Florida, where he earned a Master of Arts degree in public administration in 1971.

[3] In 2006, Patterson unsuccessfully ran for Maryland Senate in District 26,[4] losing to former state Delegate C. Anthony Muse in the Democratic primary by a 55%-45% margin.

[6] In September 2018, the Prince George's County Republican Party filed an ethics complaint against Patterson, claiming that his county government staff used a government email address to distribute an invitation to a reception featuring Democratic gubernatorial nominee Ben Jealous.

[2][10] Patterson opposed Governor Larry Hogan's proposal to construct a pro football stadium on a large parcel of federal land in Oxon Hill,[11] saying "I don't know how anyone can think about bringing the Redskins there without some drastic increase in better transportation".

[13] In the same year, he introduced various environmental bills, including: During the 2006 legislative session, Patterson voted to override Governor Bob Ehrlich's veto of the Fair Share Health Care Fund Act, which would require Walmart to pay more for employee health care.