[1][2][3] Rundberg was elected to a four-year term to represent Los Angeles City Council District 11 in 1957, ousting fellow conservative Harold Harby, the incumbent, by 17,524 votes to 10,193.

Rundberg, a conservative Republican,[4] was known for his antipathy toward beatniks, Bohemians and others with non-conformist lifestyles living in the Venice beach area of his district.

In a "resounding" City Council session in May 1957, he called them "scum" and "animals" just before the council passed an ordinance, 11-2, to restrict the noise from their bongo and Conga drums by forbidding the playing of any musical instruments on beaches or parks within 750 feet of a residence between 10 p.m. and 7 a.m. Only former policeman Tom Bradley and musician Ernani Bernardi were opposed.

In August 1968 Rundberg and fellow commissioner Robert (Nick) Starr were convicted of receiving bribes in return for their help in getting a $12 million city contract for developer Keith Smith at the harbor.

Superior Judge William B. Keene sentenced Starr to a year in jail but placed Rundberg on probation because of the latter's ill health.

[9] After having a history of heart problems,[3] he died on April 2, 1969, leaving his wife, Margaret; a son, Karl, Jr., and a daughter, Marie Pohle.