Pomeroy was born in Valley City, North Dakota, and attended Valley City State University. He then transferred to the University of North Dakota, where he earned degrees in Political Science and Law.
Pomeroy was elected to the North Dakota House of Representatives in 1980, and became State Insurance Commissioner in 1984. In 1992 he was elected to the US Congress.
Pomeroy is the ranking member on the Oversight subcommittee of the Ways and Means committee and also serves in the house committee on Agriculture.