Bob Menendez's resignation from the US Senate became official Tuesday, a much-anticipated move that follows his conviction on bribery charges in July.
The New Jersey Democrat was found guilty on 16 counts tied to a scheme where he accepted bribes, including gold bars and a Mercedes-Benz, to aid the Qatari and Egyptian governments.
He will face a potentially lengthy prison term at his sentencing in October.
Menendez, 70, has maintained his innocence and said he plans to appeal.
Menendez initially resisted calls to step down and - until last week - had kept his name on the ballot for re-election in November.
But in a resignation letter to New Jersey Governor Phil Murphy last month, the former lawmaker said he would resign Tuesday to avoid becoming a distraction.
"I do not want the Senate to be involved in a lengthy process that will detract from its important work," Menendez wrote.
Governor Murphy, a Democrat, is expected to replace Menendez with a close ally, his former chief of staff George Samir Helmy. Mr Hemly will hold the New Jersey Senate seat until a replacement is elected in November.
On Monday, Menendez filed a 30-page motion asking a federal judge to throw out the guilty verdict - the first step in what could be a lengthy appeals process.
"If sustained on such a surprisingly thin reed of evidence, these convictions will make terrible, dangerous law," the filling said. "All of Senator Menendez’s convictions must be reversed."
Menendez was first elected to the House of Representatives in 1993. He was later appointed to the Senate in 2006 by John Corzine, who gave up his seat after being elected governor of New Jersey.
At his nine-week trial this year, prosecutors told jurors that FBI agents discovered more than $480,000 (£370,452) in cash stuffed in envelopes and coats in Menendez's home, along with gold bars worth more than $100,000. Some of the bullion was presented as evidence.
His lawyers argued that the gifts he accepted did not qualify as bribes, because prosecutors had failed to prove that he took any specific action as a result of receiving them.
And they attempted to shift blame onto Menendez's wife, Nadine Arslanian Menendez, describing her as financially troubled, hoping to "get cash and assets any way she could".
Mrs Menendez also faces bribery charges but her trial was delayed so she could undergo breast cancer treatment. She has pleaded not guilty.
