"Indeed, at a time when we are all rooting for diplomacy with North Korea to succeed, walking away from the JCPOA risks losing a deal that accomplishes -- with Iran -- the very outcome that we are pursuing with the North Koreans," Obama said in a statement, CNN reported.
"That is why today's announcement is so misguided."
Trump announced on Tuesday afternoon that he was withdrawing the US from the nuclear agreement with Iran and said he would impose new sanctions.
In his statement defending the multiparty agreement with Iran, known as the Joint Comprehensive Plan of Action (JCPOA), Obama cited many who support the deal, including the US' European allies, and invoked the support of US Secretary of Defense James Mattis, who has said it is in the interest of the US to stay in the agreement.
"In a democracy, there will always be changes in policies and priorities from one Administration to the next," Obama's statement continued.
"But the consistent flouting of agreements that our country is a party to risks eroding America's credibility, and puts us at odds with the world's major powers."
The former US president was joined in his disapproval of Trump's decision on Tuesday by former vice president Joe Biden and former secretary of state John Kerry.
Biden said in a statement following Trump's announcement that the decision is "a profound mistake" and that it would put Iran on the path to developing nuclear weapons without diplomatic recourse.
"This wholly unnecessary crisis could ultimately put the safety of our country and our fellow citizens, including thousands of men and women in uniform serving across the Middle East, at risk by setting us back on a path to war with Iran," Biden said.
Kerry condemned the move by Trump to abandon the agreement he had helped forge.
"Today's announcement weakens our security, breaks America's word, isolates us from our European allies, puts Israel at greater risk, empowers Iran's hardliners, and reduces our global leverage to address Tehran's misbehavior, while damaging the ability of future Administrations to make international agreements," Kerry's statement said.
In the leadup to Trump's announcement, Kerry called for Trump to keep the agreement intact, and on Monday, Trump criticized Kerry on Twitter for what he called "shadow diplomacy."