The hospital has used emergency physicians provided by Team Health since 2007.
The move comes as part of a growing trend across the country.
Team Health physicians would sometimes be required to travel back and forth between Heartland and hospitals in other states.
"This is an exciting time for Heartland and for St. Joseph," says Dr. Robert Zink, Heartland's emergency services physician service leader. "This change will allow us to continue to offer world-class health care and provide our patients access to great care at a great cost."
Heartland hopes to complete the transition by June.