Centene Corp. has named a new top lawyer in the wake of the global health care firm's $17 billion acquisition of WellCare Health Plans Inc.

The St. Louis-based firm announced on Monday that senior vice president Chris Koster will take over as general counsel and secretary on Feb. 19. The Fortune 100 company's former GC, Keith Williamson, has been tapped to serve as president of the Centene Charitable Foundation, the company's philanthropic arm. 

Koster will oversee the company's legal functions while reporting to chairman, president and CEO Michael Neidorff. Koster, a former prosecutor who served as Missouri attorney general, joined Centene in 2017 as senior vice president of corporate services. He is a graduate of the University of Missouri-Columbia School of Law. 

"Chris has been an instrumental part of our senior team during a pivotal time of growth. His depth of experience in legal services both in the private and public sector will continue to be an asset to our company as we continue to grow and evolve," Neidorff said in a statement. 

Williamson has held the reins of Centene's legal department since 2006. He received $3.4 million in total compensation in 2017, according to Centene's 2018 proxy statement. The Harvard Law grad began his career in 1988 at Pitney Bowes, where he served as president of capital services, according to his LinkedIn profile

An active member of the St. Louis community, Williamson serves as chairman of the board of the Urban League of Metropolitan St. Louis and sits on the board of the St. Louis Art Museum. He helped found the Knowledge Is Power Program, a charter school network, and works with The Opportunity Trust to improve the St. Louis public school system. 

"I thank Keith for his 13 years as general counsel and look forward to his new role with the Foundation to help further our commitment to the communities we serve," Neidorff stated. 

Attempts to speak with Koster and Williamson were not immediately successful. 

Centene announced on Jan. 23 that it had completed its acquisition of WellCare. The company now has more than 24 million members throughout the U.S. 

After the acquisition, WellCare general counsel Anat Hakim left the company and joined Eli Lilly and Co. as senior vice president and general counsel. She began her new job on Monday at the pharmaceutical giant's Indianapolis headquarters. 

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