He was the Note & Comment Editor of the Journal of Gender, Race, & Justice.

During law school, he worked for the Federal Public Defender in Des Moines and at Tindal, Erdahl, Goddard, & Nestor in Iowa City.

[1] Following law school, Klinefeldt clerked for Robert W. Pratt of the United States District Court for the Southern District of Iowa and for Christopher Armstrong and Benjamin Kaplan of the Massachusetts Appeals Court.

[1] From 2009 to 2015, Klinefeldt served as United States Attorney for the Southern District of Iowa, to which he was nominated by Barack Obama.

[3] Following his service as U.S. Attorney, Klinefeldt joined the Des Moines office of Faegre Drinker, where he is the co-leader of the firm's white-collar criminal defense practice.