Prime Minister Rishi Sunak's governing Conservative Party suffered a crushing defeat after 14 turbulent years in power.
Sunak conceded defeat, saying the voters had delivered a "sobering verdict."
Starmer was hosted and congratulated by King Charles III July 5.
"On behalf of the Catholic community in England and Wales I should like to congratulate you on your victory in yesterday’s general election," Cardinal Nichols wrote in a July 5 statement. "I assure you of my good wishes as you take up your new responsibilities in forming and leading a government."
The cardinal, acknowledging the challenges of leadership, said the Catholic Church stands ready to work constructively with the government in matters of education and other areas that serve the common good.
"The Catholic Church has a long record of partnership with the U.K. Government, not least in the area of education where we run over two thousand schools in conjunction with the state. We look forward to this continuing and to working constructively in this and other areas with you, your ministers, and officials," he said.
According to The Associated Press, Starmer acknowledged in his first speech outside 10 Downing Street that many people are disillusioned and cynical about politics, but said his government would try to restore faith in those in power.
"My government will make you believe again," he said.
Cardinal Nichols said that the new prime minister's "previous comments about wanting a government which works with churches and faith communities have been most welcome, and I want you to know that we stand ready to play our part."
"I know that the road ahead is, perhaps, not the easiest one but I wish you well as you embark upon it. I will keep you and your family in my prayers," the prelate concluded.