Kelsi Daniell, press secretary for former Environmental Protection Agency chief Scott Pruitt, will join the communications staff of Iowa Senator Joni Ernst.
She joined Pruitt's staff nine months ago from the office of Arkansas Senator John Boozman.
Pruitt, who faced a slew of ethics probes, resigned his position July 5 after rolling back Obama protections against climate change and industrial pollution.
In his resignation letter, Pruitt hit “the unrelenting attacks on me personally, my family, are unprecedented and have taken a sizable toll on all of us.”
Ernst was among Republican critics of Pruitt, saying he "is about as swampy as you get here in Washington, DC, and if the president wants to drain the swamp, he needs to take a look at his own cabinet."
In accepting Pruitt's resignation, President Trump tweeted "within the agency Scott did an outstanding job."