The panel will still have only 10 members despite Democrats winning two seats in the 2012 elections. Sen. Jim Webb (D-Va.) is retiring from the Senate.
Murphy served on the House Foreign Affairs panel on the Middle East and South Asia during his six years in the House.
The top spot on the committee might also come open if Sen. John Kerry (D-Mass.) gets the nod to replace Hillary Clinton as secretary of State. That would leave Sen. Robert Menendez (D-N.J.) as next in line to take over because the only more senior Democrat, Sen. Barbara Boxer (D-Calif.), is set to retain her chairmanship of the Senate Committee on Environment and Public Works.