The Pennsylvania senator released a lengthy statement on Saturday in light of a federal judge’s dismissal of the Trump campaign’s lawsuit challenging the election results in Pennsylvania.
US District Court judge Matthew Brann ruled on Saturday that Mr Trump’s campaign had failed to demonstrate there had been widespread voter fraud in the state during the election.
“President Trump has exhausted all plausible legal options to challenge the result of the presidential race in Pennsylvania,” Mr Toomey said in a statement, before going on to recognise Mr Biden as the election winner.
“I congratulate President-elect Biden and Vice President-elect Kamala Harris on their victory. They are both dedicated public servants and I will be praying for them and for our country,” he said.
Mr Biden was announced as the winner of the election on 7 November by major news platforms but Mr Trump has yet to concede defeat.
“Unsurprisingly, I have significant policy disagreements with the president-elect,” Mr Toomey said.
“However, as I have done throughout my career, I will seek to work across the aisle with him and his administration.”
The senator praised the achievements of the president during his time in office including his work on the economy, peace agreements and overseeing the development of a coronavirus vaccine.
“To ensure that he is remembered for these outstanding accomplishments, and to help unify our country, President Trump should accept the outcome of the election and facilitate the presidential transition process,” he said.
Mr Toomey is the fifth Senate Republican to congratulate Biden on winning the 2020 presidential election, following Mitt Romney, Lisa Murkowski, Susan Collins and Ben Sasse.
Other Republican senators have said they think it likely that Mr Biden will be inaugurated on 20 Janunary.
However, a number of GOP lawmakers have remained silent amid Mr Trump’s threats of legal challenges alleging fraud in swing states that he claims cost him victory.
The lawsuit dismissed in Pennsylvania is one of dozens filed by Mr Trump and his Republican allies in the aftermath of the election in a bid to overturn it.
The campaign has not provided evidence for its claims of widespread and coordinated electoral fraud.
He added that he “has no authority to take away the right to vote of even a single person, let alone millions of citizens”.