[2] In 1882, he moved west and settled in Moorhead, Minnesota, where he was admitted to the bar in November 1883.

[2] In 1884, he moved to Dakota Territory and opened a law office in Tower City, where he also served on the local school board.

Following the sudden death of Mitchell in 1890, Clapp was appointed to fill the remainder of the term and served as the second North Dakota Superintendent of Public Instruction.

[5] After his time with the Department of Public Instruction, Clapp returned to Fargo and continued to practice law.

He was a prominent lawyer in the Fargo area and was a member of the Cass County Bar Association.