The staunch Trump ally has left the influential Office of Information and Regulatory Affairs after a year of slashing rules.

Jeffrey B. Clark oversaw the dismantlement of government restrictions on greenhouse gas emissions and water and air pollution. He had also faced a criminal probe in connection with the 2020 election.

WASHINGTON — Most Americans don't know Jeffrey Clark — the environmental lawyer whom former President Donald Trump wanted to take over the Justice Department to aid his effort to overturn the 2020 ...