Kline is an anti-abortion Republican who served as attorney general in 2003-07 and launched an investigation of Dr. George Tiller's abortion clinic months after taking office.
After failing to win re-election in 2006, Kline became Johnson County district attorney to replace Paul Morrison, a former Republican who switched parties and beat Kline in the attorney general's race.
Kline lost his bid for a full term as Johnson County district attorney in the Republican primary last year. He leaves office on Monday, the same day he begins his job at Liberty.
Kline met Liberty's law school dean, Mathew Staver, when he was attorney general.