He was publically sworn in at the White House after being appointed on Saturday.
His appointment has been controversial with a number of historical sexual assault allegations being made against him.
Kavanaugh has denied the accusations which date back to when he was a teenager.
His swearing in was attended by Franklin Graham.
Writing on social media, he said: "Last night I had the privilege of attending the swearing-in ceremony of U.S. Supreme Court Justice Brett Kavanaugh at the White House.
"He and his wife Ashley have two wonderful daughters who were also there for this special evening.
"Would you pray for Justice Kavanaugh and his family? I'm sure he will serve America well. Also pray that God will bring healing to our divided nation."
At the White House event, Donald Trump apologised to Kavanaugh over what he called the 'unfair' treatment he received during the confirmation process.
Thousands had gathered over the weekend to protest against his appointment.
The US-based National Council of Churches had also spoken out against him claiming he had "disqualified himself" through his actions. It also accused him of "outright falsehoods".
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