Murphy also introduced Christine Norbut Beyer, to lead the Department of Children and Families, encompassing child welfare and behavioral health and domestic violence programs.
Johnson, a North Cape May native, would oversee the sprawling Human Services department, which manages the $15 billion Medicaid and other programs for the poor and for people with developmental disabilities.
Phil Murphy's latest cabinet pick once again highlights diversity
Johnson served on the White House Domestic Policy Council health team, according to several online biographies. Previously, she was the research scientist and lecturer at the George Washington University's Center for Health Policy Research. She holds a master's degree in government from the University of Virginia.
Beyer said she got her start as an intern at what was then known as the Division of Youth and Family Services. She later returned in 2003, as the state embarked on a multi-billion-dollar, court supervised overhaul of what many officials agreed was a failing entity.
Murphy introduced the nominees during a press conference at HomeFront in Ewing, a major social service and homelessness prevention agency serving Mercer County.
Born appointments require approval of the state Senate.
Murphy, a Democrat, will take office on Jan. 16, succeeding Republican Gov. Chris Christie.
Susan K. Livio may be reached at slivio@njadvancemedia.com. Follow her on Twitter @SusanKLivio. Find NJ.com Politics on Facebook.