Ripperger, the office's chief deputy, was elected on an unanimous vote by the Polk County Conference Board. He was chosen from four candidates in a campaign that brought the attention of U.S. Sen. Tom Harkin and lobbying efforts by other elected officials.
Ripperger has spent 34 years with the assessor's office and was the interim county assessor after Maloney retired April 15.
Ripperger had been endorsed by a three-member board that interviewed candidates on April 9. Maloney also endorsed Ripperger and had expressed some disappointment that the selection of his successor became a political issue.
In a release, Ripperger said Maloney "has taught me the importance of organizational transparency in maintaining the public trust."
He will serve the remaining three years of Maloney's six-year term, then stand for reappointment.
The Conference Board is made up up representatives from all Polk County school districts, the mayors of each city in the county and the board of supervisors, with the preferences of each group condensed to one final vote from each.
Urbandale Mayor Robert Andeweg said Greater Des Moines mayors were unanimous in their support for Ripperger, but he said all of the candidates were qualified for the office.
Prior to Monday's vote, considerable support had emerged for Gregory Lynch, the current Ames city assessor. Lynch lives in Greater Des Moines and once worked in the Polk County assessor's office.
Andeweg said that after the three groups caucused, "there was not much discussion or debate" leading to the final vote.
Commercial real estate professionals were keen observers of the the lobbying campaign that led to the vote, with many believing that Ripperger, after more than three decades in the office, should succeed Maloney.
"I think they made the right call," said Kurt Mumm, president of NAI Optimum in West Des Moines. "Randy was at Jim's right hand for a long time. If it wasn't working, I'd say bring somebody in from the outside."