Johnson, who is also managing director of property finance, will step down from the board and relinquish his roles immediately, but will formally depart on April 30, according to a statement from the lender.
Two new members of the executive committee were also announced. Karen Bennett will join as managing director of commercial property finance and Jeremy Law will become managing director of residential finance.
Ian Cowie, managing director of business finance will take responsibility for development finance.
Johnson put the decision down to the change in ownership and passing the leadership of the business on to a “new generation”.
“Shawbrook has played a huge part in my professional life and that of my family and the recent change of ownership presents an opportunity to pass the leadership of the property business to a new generation,” he said.
“I appreciate the support that I have had from the board in making this difficult decision and I am sure Karen, Jeremy and Ian will continue to provide the perceptive and thoughtful underwriting and great customer service that have been the hallmarks of the business over the last few years and I wish them all well.”
Shawbrook CEO Steve Pateman said: “Stephen has been an integral part of Shawbrook since inception and has made a significant contribution during that time helping to build a bank that now has assets of over £5.0bn.
“The recent change of ownership has created an opportunity for Stephen to take some time out with his family and we wish him all the very best for the future. We are fortunate to have strong successors in place; Karen Bennett has been with Shawbrook since 2004 and has led our commercial property business for the last two years while Jeremy Law has five years of experience in residential mortgages from his time at the Post Office.”
Chairman Iain Cornish added: “The board would like to thank Stephen for the important contribution he has made over the last 15 years and in particular during the IPO in April 2015. We wish him and his family well.”