[3][4] McCarter was a member of the St. Clair County board from 2000 until 2009, when he was appointed to the Illinois State Senate.

"[5] McCarter and his wife, Victoria, lived and worked in Kenya for Each1Feed1, a Christian ministry that gives care and education for orphans and widows, in 1987–1988 and built Faith Medical Clinic.

"[7] On May 31, 2011, McCarter accused Democratic state Sen. Mike Jacobs of punching him after a debate over an electricity rate increase, a claim Jacobs denied by saying in a televised interview that "the senator was full of shit" and "someone who couldn't even really polish my shoes".

Jacobs also said this information had been fully disclosed, his constituents were aware of it, "and they would make a decision based on that".

However, Jones failed to adequately meet the petition filing requirements and did not appear on the ballot.

The day after Archer Daniels Midland and Tate & Lyle, both major employers in McCarter's senate district, expressed concern about the project, he changed his position and voted against the bill.

In response Kurt Erickson of The Southern Illinoisan wrote, "In the process, he became the quintessential politician that voters love to hate: He said one thing on the campaign trail and then reversed himself once safely elected.

"[18][better source needed] In May 2012, McCarter voted against a bill in the state senate that would have encouraged public schools to implement anti-bullying programs.

But there are programs throughout the United States, used in some high schools and universities, that really have just a pro-homosexual agenda, and nothing but that.

"[20] Prior to announcing his candidacy for Congress, McCarter used about $33,000 from his state campaign fund to pay a political consultant.

[34] He considered, but ultimately declined, a run for U.S. Senate in 2022 special election in Oklahoma.

[35] McCarter and his wife Victoria lived in Lebanon, Illinois before moving to Oklahoma after his ambassadorship.