[3] In 1969, Swenson won the Mayoral race in Harrisburg in an upset against the Harvey Taylor machine and took office in 1970, becoming the first elected Democrat in 58 years.

The Patriot News reporter Paul Beers wrote that within his first month he "established his magisterial presence, and within the first year he was regarded as the mayor of the entire Harrisburg area, invited to cut many of the ribbons in suburbia.

[4] Swenson was praised for navigating and calming anxieties after the 1969 Race Riots, Harrisburg Seven Trial, and then Flood of 1972 caused by Hurricane Agnes.

It was widely noted that he put managing before politics, and retained competent workers at City Hall regardless of party.

[4] Some criticized him of weak Democrat allegiance, calling him a "Republicrat," but in 1973 he was reelected for a second term, and promptly assisted in establishing the Capital Area Transit with the folding of the Harrisburg Railways.