 John Schneider portrays Jonathan Kent , Martha 's husband and Clark 's adopted father . He goes to great lengths to protect his son 's secret , which includes : almost killing a reporter , in the season two premiere , who was going to expose Clark 's secret to the world , and making a deal to allow Clark 's biological father , Jor @-@ El , to take Clark to fulfill his destiny if Jor @-@ El gave Jonathan the power to bring Clark home — Clark had run away after believing his parents blamed him for Martha 's miscarriage . As a result , season three 's " Hereafter " explains that Jonathan 's heart was strained while he was imbued with all of Clark 's powers . In season five , Jonathan decides to run for a seat in the Kansas Senate against Lex Luthor . In the season five episode " Reckoning " , Jonathan wins the senatorial seat , but after a physical altercation with Lionel Luthor , whom he believed was trying to exploit Clark 's abilities , Jonathan suffers a fatal heart attack . 
