For six months, the Tesla Motors and SpaceX founder contributed to Trump's Strategic and Policy Forum -- an executive advisory body comprised of many American business leaders. He has also advised the president on manufacturing jobs and infrastructure.
Musk, a staunch environmental advocate, took severe criticism for agreeing to work with Trump -- but he'd always defended his membership on the presidential councils. Thursday, however, after Trump announced he would pull the United States out of the global climate change accord, Musk indicated that he'd had enough.
"[I am] departing presidential councils. Climate change is real," he tweeted. "Leaving Paris [accord] is not good for America or the world."
Musk said earlier this week that he would consider quitting the councils if Trump went ahead with the withdrawal.
Like Musk, many American corporate leaders favored keeping the United States in the agreement -- which was reached in Paris in 2015 and signed by nearly 200 countries -- by asking Trump in an open letter this week to reaffirm commitment to the accord.
The unprecedented effort establishes significant global standards and requires signatories to abide by them in an effort to mitigate climate change. The United States signed the deal under former President Barack Obama in-line with his ambitious agenda against climate change.
Trump's decision Thursday was applauded by some conservatives and the U.S. energy industry -- who have argued that the deal would be a job-killing drain on the U.S. economy.
In his announcement, Trump said he is open to renegotiating the Paris agreement and that he "cares deeply" about environmental matters.
"It fails to live up to our environmental ideals," he said of the existing pact.
"We're getting out, but we will start to negotiate and see if we can make a deal that's fair."