Metcalf was born in Marysville, Washington on 30 November 1927. He received bachelor's degrees from Pacific Lutheran University in 1951 and a master's degree from the University of Washington in 1966. He entered the Washington State Senate in 1966 and served until 1974, as well as again from 1980 to 1992. He twice ran unsuccessfully against incumbent Democrat Warren G. Magnuson for United States Senate in 1968 and 1974. In 1992, Metcalf again tried to gain national office, but was unable to defeat incumbent Democrat Allan Swift in the House election.

With Swift retiring from the House in 1994, Metcalf ran again. This time, he was elected. He was also re-elected in 1996 and 1998. A supporter of term limits such as those proposed in the 1994 Contract with America (which Metcalf had signed), Metcalf did not run for re-election in 2000.

During his political career, Metcalf was known as a paleoconservative and supporter of returning to the gold standard. In his last term in office (1998-2000) he surprised some observers by taking some positions unusual for a conservative Republican, including voting to close the School of the Americas, working with Paul Watson and Sea Shepherd to protest whaling by the Makah tribe and hiring Washington state antiwar speaker and writer Craig B. Hulet as a special assistant.