President Trump made the comments during a joint press conference with Canadian Prime Minister Justin Trudeau.
The test is the first experimental launch North Korea has undertaken since President Trump took office in January.
In a statement from North Korea's army, the test was referred to as a "show of force" by Pyongyang against the "rigid attitude" of the Trump administration concerning the country.
Following the launch, the Pentagon announced that the missile was a short-to-medium range ballistic missile, which doesn't pose a threat to the mainland United States.
However, the statement noted that US forces are on alert against North Korean provocations and the US will "work closely with our allies, Japan and South Korea, to maintain security."
White House officials said the president was briefed on the situation and they are "closely monitoring developments."
According to a Trump administration official, the US has a variety of response options to the missile launch, including sanctions and increasing the US's military presence in the area.
National security implications over iceberg wedge salads
The only story bigger than the missile launch itself was the story of President Trump receiving news of the launch.
Images on social media and news outlets around the world appeared to show President Trump receive news of the launch while dining—with Japanese Prime Minister Shinzō Abe—at his Florida resort, the "Mar a-Lago."
The club members snapped photos and posted them to Facebook with detailed narratives about what they were seeing unfold before their eyes Saturday night in Palm Beach, Florida.
"HOLY MOLY !!! It was fascinating to watch the flurry of activity at dinner when the news came that North Korea had launched a missile in the direction of Japan," wrote one diner.
In light of the various social media posts and pictures circulating around the web, complaints about the president acting irresponsibility with classified material in public began to surface.
"There's inconsistency all over the place in terms of how much Donald Trump raised national security on the campaign trail and how he is now operating as president," said Brian Fallon, who was Clinton's campaign spokesman. "And there's hypocrisy from congressional leaders who demagogued this issue, constantly accusing Hillary Clinton of doing something that was far less egregious than this very conspicuous departure from security protocols."
House Minority Leader Nancy Pelosi wrote on Twitter, "There's no excuse for letting an international crisis play out in front of a bunch of country club members like dinner theater."
The chairman of that committee, North Carolina Sen. Richard Burr, seemed dismissive of the concerns.
"If the president didn't speak of things that couldn't be spoken of in public, then there's no problem with it," he said. He also said he saw no immediate need for a briefing on the matter.