The announcement came just hours after a source familiar with Grimm's thinking told CNN he would resign "sooner rather than later," after the New York Daily News broke the news
of Grimm's plans to step down.
"After much thought and prayer, I have made the very difficult decision to step down from Congress effective January 5th, 2015. This decision is made with a heavy heart, as I have enjoyed a very special relationship and closeness with my constituents, whom I care about deeply," Grimm said in a statement issued shortly before midnight by his office.
The Staten Island congressman was indicted in April on 20 counts relating to his health food restaurant, Healthalicious, including charges that he filed false tax returns; engaged in mail fraud, wire fraud and perjury; and knowingly hired undocumented workers.
House Speaker John Boehner called Grimm's decision to step down "honorable" in a statement on Tuesday.
"I know it was made with the best interests of his constituents and the institution in mind, and I appreciate his years of service in the House," Boehner said.
A Republican congressional source said Boehner and Grimm spoke Monday before Grimm announced his plans to resign.
During last Tuesday's hearing, Grimm pleaded guilty to one count of aiding in the filing of a false tax return, a plea that's expected to bring him months of jail time.
In the statement announcing his plans to resign, Grimm said that "the events which led to this day did not break my spirit, nor the will of the voters," but that he feels he won't be able to serve effectively in the new Congress.
"However, I do not believe that I can continue to be 100% effective in the next Congress, and therefore, out of respect for the Office and the people I so proudly represent, it is time for me to start the next chapter of my life," he said.
The decision to resign marks a change of heart for the Staten Island Republican, who rejected calls to step down after he entered his guilty plea.
He apologized for his actions and took responsibility, and said that the unpaid taxes from a New York restaurant he once owned were a mistake.
"As long as I'm able to serve I'm going to serve," he said. Grimm was re-elected in November and was to be sworn in to a new term in January.
While there's nothing in the Constitution or House Rules barring felons from serving in Congress, the situation created an unwanted headache and negative attention for Boehner as he seeks to head into the new Congress starting with a clean slate.
While he gave up his seat on the House Financial Services Committee after he was charged, Grimm repeatedly insisted he would be "fully exonerated."
According to the Daily News
, however, Grimm admitted to the conduct alleged in his 20-count indictment in a document to the court.
The indictment came down just months before what was already expected to be a tough re-election fight for the perennial Democratic target. His Staten Island-area district went for President Barack Obama in 2012, but despite the cloud of the indictment hanging over his head, Grimm pulled out an easy win over his Democratic challenger in November.
His re-election and subsequent guilty plea created problems for Boehner, who — along with then-Majority Leader Eric Cantor — in 2010 promised to institute a "zero tolerance" policy
for ethics violations within the GOP caucus, which had dogged the party and contributed to its steep losses in the 2006 and 2008 elections.
Indeed, in previous situations
where House Republicans admitted to criminal or personal ethical lapses, Boehner has worked privately to encourage those members to step aside on their own.
But Grimm's guilty plea wasn't the only headache he's caused Boehner over the past year. He drew negative headlines last January when he was caught on camera threatening to throw a reporter off a balcony and break him in half "like a boy," after the reporter asked about an investigation into his campaign finances.
Grimm's resignation will spark a competitive special election for his seat, and potential contenders have already begun lining up.
Former Democratic Rep. Michael McMahon, who narrowly lost to Grimm in 2010, has reportedly expressed interest
in a bid for his old seat.
Republican candidates, according to the Daily News, could include Staten Island District Attorney Daniel Donovan, Assemblywoman Nicole Malliotakis and state Sen. Andrew Lanza.