 John Glover portrays Lex 's father , Lionel Luthor . Lionel initially sends his son to Smallville to run the local fertilizer plant , as a test . When Lex succeeds in making a profit for the first time in years , Lionel closes the plant down completely and blames it on Lex 's poor managerial skills . As the series progresses , Lionel becomes interested in the Kawatche caves , which have Kryptonian symbols painted on their walls ; his interests also extend to the secrets Clark keeps . After being possessed by Jor @-@ El in the season five episode " Hidden " , Lionel begins assisting Clark in keeping his secret hidden from Lex . In season seven , Lionel is murdered by Lex , who realizes that his father has been covering up the truth about an alien visitor . 
