Mr. McCallister announced his resignation earlier this year, attributing the decision to personal reasons and wanting to be closer to family, according to the report.
Mr. McCallister was named CEO of Johnson County Healthcare Center in 2019.
Johnson County Healthcare Center includes a 25-bed critical access hospital, a medical clinic, nursing home and a home health and hospice department.
Laurie Hansen, RN, director of administration, was chosen as interim CEO of the organization, effective May 27.