Trump told reporters at the White House that he had "a very good relationship" with Rosenstein and was eager to speak with him aboard Air Force One on a flight to Florida for the International Association of Chiefs of Police conference. It is not unusual for senior Justice Department officials to join Trump at such events.
On the campaign trail and while in the White House, he has often told the story of a Chicago motorcycle cop, "a tough cookie" in the president's words, who told him he could solve the city's gun violence problems "in a couple of days" if cops were allowed to do their jobs.
Rosenstein, who oversees the investigation of Russian election interference led by special counsel Robert S. Mueller III, offered to resign last month after reports that he contemplated secretly recording conversations with the president.
Hours before Trump addressed the police chiefs, a handful of protesters outside the Orange County Convention Center waved signs reading "Sexual Predators Belong in Jail Not as President or Supreme Court" and "We Wish You Were Fake News".
Aaron Jimenez, a police chief in St. Ann, Missouri, said he feels Mr. Trump has supported law enforcement more than past presidents.
During his speech, the president said the duo "had a good talk" on the plane.
Washington was briefly abuzz on September 24 when Rosenstein headed to the White House to meet with chief of staff John Kelly, but reports that the retired Marine Corps general was handing him a pink slip turned out to be inaccurate.
Rosenstein assumed supervision of the investigation after Attorney General Jeff Sessions recused himself because of his own contacts with Russia's ambassador to Washington while serving as a Trump campaign adviser became public. He blamed the ACLU for tying the hands of police in the city, and said that "Stop and Frisk" works and should be considered there.
"We have two years back-to-back with significant declines, but not to the level I want to see as mayor or Superintendent [Eddie] Johnson wants to see", he said. So far, most Republicans are sticking by Trump, but if the party concludes his antics since taking office contributed to the GOP losing the House - and possibly the Senate - then the impeachment math could swing against him.
"I said, 'Brett, congratulations".
Rosenstein's visit to the White House on September 24 sparked a false alarm about the No. 2 Justice Department official being fired or resigning.
Watch the clip above, courtesy of Fox News.