Lionel Luthor

Lionel Luthor was the billionaire founder and CEO of Luthor Corp. Lionel was also the husband of Lillian Luthor as well as the father of Lex and Lena Luthor. After he passed away, his son inherited the family company.

Early life
Lionel founded and administrated the multibillion-dollar corporation known as Luthor Corp. At some point in his life he married Lillian, a brilliant physician, and the two had a son, Lex. However, sometime after their son was born, Lionel started having an affair with an unnamed woman, who eventually got pregnant. Lillian found out about it when she surprised him with his mistress on a business trip. Wanting to rebuild things with his wife, Lionel decided to send his lover away after they paid her to keep quiet about the affair.

Bringing Lena home
Four years later, the woman died and Lionel decided to adopt his illegitimate daughter, Lena. Despite Lillian's protests, Lionel brought the little girl to the Luthor Mansion, where she was introduced to her brother Lex; although she was clearly upset about it, Lillian went along with it.

Over the next years, Lena was left unknowing of the truth on her parentage and convinced that she was simply adopted. Lionel is said to have loved deeply his daughter, always favoring her over Lex, and Lena thought of him as "a saint". According to Lillian, he prevented his wife from ever forming a close relationship with Lena because he felt guilty seeing his beloved wife together with the child born of his affair, though that's more likely a lie. He later died for unknown reasons.

Legacy
Years after his death, Lex Luthor succeeded his father Lionel as the CEO of Luthor Corp; however, Lex fell from grace after he went insane and killed many innocent people in his war against Superman. Lex was ultimately stopped by the superhero when he exposes his crimes to the public and incarcerated for 37 consecutive life sentences. Lionel's daughter Lena Luthor then took over the company and renamed it L-Corp, hoping to take it in a new positive direction.

Personality
Although Lionel was an unfaithful husband and cheated on his wife Lillian with an unnamed woman sometime after their son Lex was born, resulting in the birth of his second child and only daughter Lena, according to the latter he was a good man; implying that Lionel was kind, caring, selfless, moral and honorable, the opposite of his wife and son, despite the fact that he never revealed to Lena that he was her biological father (prior to his death) Lionel was always loving towards her and treated her warmly, unlike Lillian who is always cold to Lena because she is a reminder of Lionel's affair. However it's strongly suggested that he had a difficult relationship with his son Lex and always favoured Lena over him.

Apparently Lionel loved Lillian deeply and he lifelong felt extremely guilty for having cheated on her, to the point he was the one who prevented his wife from ever forming a close relationship with Lena, as he couldn't stand seeing Lillian together with the child born of his affair; though that's more likely a lie created by Lillian.

Trivia

 * In stark contrast to all the other adaptations of the character, where Lionel Luthor has a full set of long hair, in the show he is represented bald just like his son, implying that Lex's baldness is an inherited trait and not caused by an accident as generally represented.

Behind the scenes

 * In the DC comics, Lex Luthor's father is named Jules Luthor. He debuted in Superman's Girlfriend, Lois Lane #23 (February, 1961) and was created by Jerry Siegel and Kurt Schaffenberger. In later incarnations he usually remains unnamed.
 * The character was first given the name "Lionel" on the TV show, Smallville, on which he is played by John Glover. Due to the popularity of this portrayal of the character he was given the name "Lionel" in the comics too.