Johnson, in his early education, was taught by a free colored woman, Miss Nancy Walton.

He was the first graduate of the law school at Shaw and served as dean, following John S. Leary in that capacity.

Johnson became active in the Republican Party and served a term on Raleigh's city board of aldermen.

In 1899, Johnson wrote his second textbook entitled History of the Negro Soldiers in the Spanish American War and Other Items of Interest.

In 1904, Johnson wrote a utopian novel entitled Light Ahead for the Negro, which describes a 2006 future in which there is no anti-black discrimination.