Jonathan Kent (John Schneider) owns the Kent Farm in Smallville, Kansas, where he takes pride in being a hard-working farmer. He is a loyal, loving husband to his wife, Martha (Annette O'Toole) and a caring father to his adopted son, Clark (Tom Welling). Jonathan will do anything to protect his family, which tends to make him butt heads with Lionel Luthor (John Glover), a man with a large fortune built on selfishness and corruption. He also has conflicts with Jor-El (Terence Stamp), Clark's biological father. Jonathan is a key component in Clark's life and always tries to do what is best for his son.
Although Jonathan wants to be the best possible father he can to Clark, he is often conflicted because of Clark's alien origins. When Clark becomes a teenager his powers start to develop and Jonathan must tell Clark where he really came from. Because of his son's special abilities, Jonathan is reluctant to let Clark do seemingly normal teenage activities for risk of exposing his secret. For instance, Clark wants to try out for the football team during his freshman year but Jonathan will not give him permission because he is afraid Clark might accidentally injure others with his super strength.
When Clark befriends Lionel's son, Lex (Michael Rosenbaum), Jonathan is less than thrilled and does not want Clark to associate with him. His good nature is also put to the test when he starts dealing with Clark's birth father. Jor-El claims that Clark has a greater destiny than just being on Earth. Jonathan wants to protect the human side of Clark but he cannot fully comprehend the alien side. He also knows that Clark's real father might be able to give him something Jonathan can not. He is forced to make a deal with Jor-El when Clark is corrupted by red Kryptonite and starts using his powers for evil. Jonathan is given the power to save Clark from himself, but in return he has to let Clark go with Jor-El when the time comes to fulfill his destiny.
After one heart attack, which he survives, Jonathan's heart problems resurface and he eventually dies of another heart attack. Even after his death, he comes to Clark in dreams and visions to guide him.
Jonathan Kent in a key factor in Superman's origins. He raised Clark with good moral standards so he would be honest and hard-working. Clark respected his father and developed the same moral compass and value structure. When he was faced with choosing evil over good, it was Jonathan's stong influence that led Clark to become a hero.
"We didn't find you Clark. You found us."
"No, son. It doesn't matter where you came from, or what you can do. You'll always be Clark Kent."
"Clark... believe me you have nothing to be sorry about. I lived a full wonderful life. I had everything a husband or a father could ever possibly dream of. I am so very proud that I died protecting you."