HARRISBURG — A former Pennsylvania state lawmaker was named Friday to run the massive Department of Public Welfare after two years of missteps, embarrassments and federal scrutiny over why tens of thousands of children disappeared from Medicaid rolls.

Bev Mackereth will be the department’s acting secretary, Gov. Tom Corbett said. She will succeed Gary Alexander, a Rhode Island resident who told The Associated Press earlier this week that he had planned to leave the post. His last day will be Feb. 15.

Mackereth, of York County, served eight years as a Republican in the state House of Representatives and has managed the department’s Office of Children, Youth and Families since November 2011. She also served as executive director of York County Human Services.

Even after the Republican governor nominated Alexander in 2011, Rhode Island officials were disputing his claims of cost-cutting achievements in his previous role as that state’s secretary of Health and Human Services.

Alexander’s efforts to cut costs in Pennsylvania frequently drew criticism from Democrats and advocates for the poor and disabled.