Pruitt was equally complimentary of the president in his resignation letter, stating that God both led Trump to the White House and him to serve in Trump's administration.
Democrats and environmental groups decried Wheeler as an apologist for the coal industry.
"I look forward to the confirmation of the next head of the EPA".
"It is extremely hard for me to cease serving you in this role first because I count it as a blessing to be serving you in any capacity, but also because of the transformative work that is occurring", he wrote in his resignation letter obtained by Fox News.
President Donald Trump says he has accepted the resignation of scandal-plagued Environmental Protection Agency Administrator Scott Pruitt. His most prominent former client, coal magnate Robert E. Murray, is an aggressive opponent of important air-pollution rules that the Obama EPA tried to impose and that Mr. Pruitt began the process of ripping up.
Trump's inner circle this year became frustrated by the torrent of news reports about Pruitt's controversies. Many of the EPA regulations Pruitt scraped or delayed had not yet taken effect, and the tens of thousands of lost coal mining jobs the president pledged to bring back never materialized. Environmental groups expressed dismay when he joined the federal agency, and Pruitt has since sought to roll back various environmental regulations, including Obama-era vehicle emission standards.
Republican Senator Jim Inhofe, from Pruitt's home state of Oklahoma, praised Pruitt's efforts to cut red tape for industry.
"From moving to roll back strong fuel economy standards, to repealing the Clean Power Plan, to undermining chemical regulation, to suppressing climate science, to advocating for USA withdrawal from the Paris climate agreement, Scott Pruitt made the EPA stand for Every Polluter's Ally", he said in a statement.
At the time, the president was feuding with Sessions over the AG's decision to recuse himself from the Russian Federation investigation, according to CNN, which cited three people familiar with Pruitt's pitch.
Jennifer Kaplan, a spokesperson for EPA Inspector General Arthur Elkins, said Thursday that the office was "assessing and evaluating" its ongoing audits and investigations in the wake of Pruitt's departure. He was also found by the Government Accountability Office to have violated federal spending law when purchasing a $43,000 soundproof phone booth in his office. "Americans will not tolerate another EPA administrator whose primary goal is to fight the core mission of the EPA".