Davies will take up the role after the firm's 2016 preliminary results announcement next spring and current finance boss Mark Gregory will step down at the same time.
Gregory will remain an employee of the company until 31 August, L&G said in a statement, to help smooth over the handover process.
Davies leads the European risk and actuarial insurance services practice at EY, where he has worked since 2004.
Before joining EY, he held several senior actuarial roles at Swiss Re Life & Health.
L&G chairman Sir John Kingman said:
I am delighted Jeff has been appointed as group chief financial officer. He has deep insurance experience and expertise, and will be an excellent addition to the group board as we take Legal & General forward on the next stage of our strategy of growth. Mark has been an outstanding group chief financial officer. I would like to thank him for agreeing to stay with Legal & General until the summer.
Last month, L&G completed its £1.1bn Rolls-Royce pension buyout.