He was an assistant professor for the Boston University School of Public Communications from 1966 to 1973.

He served as an assistant commonwealth attorney general, specifically as Chief of Consumer Protection Division of Massachusetts from 1971 to 1973, and as a justice of the Superior Court of Massachusetts from 1973 to 1979.

[1] On January 25, 1979, President Jimmy Carter nominated Nelson to a new seat on the United States District Court for the District of Massachusetts created by 92 Stat.

He was the first African American to be appointed a federal judge in Massachusetts.

[2][3] He assumed senior status due to a certified disability on September 27, 1991, serving in that capacity until his death on October 21, 1998, in Framingham, Massachusetts.