He served in the United States Army Air Forces during the Second World War as a bomber pilot.

His plane was shot down and he received a Purple Heart, nine battle stars, and the Air Medal with four oak leaf clusters.

A federal anti-nepotism law, sponsored by Smith, was enacted in 1967 prevents public officials, including the president, from appointing any relative to head an executive agency.

However, the 1990s redistricting pushed him into a district covering the southwest quadrant of the state from Des Moines to Council Bluffs, an area that he did not know and that did not know him.

He was reelected in 1992, but was defeated in the Republican landslide of 1994 by Greg Ganske, mainly due to heavy losses in the western portion of the district.

At the time of his defeat, he had represented Iowa in Congress longer than anyone in the state's history; he has since been passed by Democrat Tom Harkin, who served for a combined 40 years in the House and Senate, and by Republican Chuck Grassley, who as of 2023 has served for over 48 years in the House and Senate.