- "I thought we had discussed this."
"We did. And this is what we're doing. Lena, this is your new mother."
- —Lillian Luthor and Lionel Luthor[src]
After Lionel passed away, his son Lex inherited the family company.
Lionel founded and administrated the multibillion-dollar corporation known as Luthor Corp in Metropolis. At some point in his life, he married Lillian, a prominent physician, and sometime after 1983, the two had a son, Lex. A renowned and worldly man, Lionel traveled a lot during his life and befriended many famous personalities and world authorities. At one point, he received a prized fountain pen as a gift from the King of Jordan.
Sometime after Lex's birth, Lionel started having an affair with an unnamed woman. When Lex was 7 years old, his dog Ignatius fell ill and had to be put down, however, feeling that he was too sentimental, Lillian forbidden the child to be present at the procedure, forcing him to go on a business trip with Lionel instead. There, they were accompanied by Lionel's lover and he gave her all of his attention. At first, Lex swore to himself that he would loathe the woman for taking his father from him when he needed him the most, but couldn't keep his promise because of how kind she was to him.
In 1993, Lillian found out about Lionel's affair when she surprised him with his mistress on a business trip. Wanting to rebuild things with his wife, Lionel chose to send his lover, now pregnant, away after they paid her to keep the affair a secret.
Bringing Lena home
Over four years later in 1997, Lionel discovered his lover had died and decided to adopt their illegitimate daughter, Lena, not wanting her to be placed into foster care. Despite Lillian's protests, Lionel brought Lena to the Luthor Mansion, where the little girl was introduced to her half-brother, Lex. Although clearly upset about this, Lillian went along with his decision, to which Lionel thanked her. He then proudly watched as Lena and Lex played chess together.
Over the years, Lena was left in the dark of the truth of her parentage and convinced that she was simply adopted. Lionel was said to have loved his daughter deeply, always favoring her over Lex, and Lena thought of him as "a saint". Lillian claimed that Lionel prevented her from ever forming a close relationship with Lena because he felt guilty seeing his beloved wife together with the child born of his affair. However, this is more likely a lie since Lillian actually kept her distance from Lena due to the latter's parentage.
According to Lex, he had grown to hate his father, not because he betrayed the Luthor family, but because he stayed with them and started heavily drinking. Lionel's drinking became a problem for his family, as Lena thought it was something Lex would want to bond with her over. On one occasion, in order to please Lex, Lena stole Lionel's prized fountain pen while he was drunk and to escape Lionel's wrath, they hid on their tree house, were Lex comforted Lena, telling her that their father could not climb when he was drunk and that one day he would have build a house on the Alps for her in order to keep her safe.
Lionel later passed away alone.
Years after Lionel's death, Lex Luthor succeeded his father as the CEO of Luthor Corp. However, Lex fell from grace after he descended into insanity in his war against Superman. Once Lex was incarcerated, Lionel's daughter, Lena Luthor, took over the company and renamed it to L-Corp, hoping to take it in a new, positive direction.
Lillian used the memory of Lionel's death to force Lex to make Lena immune to his brainwashing program, "I Love Lexi", by reminding that Lionel died without family around but surrounded by sycophants.
Although Lionel was an unfaithful husband and cheated on his wife, Lillian Luthor, he was a good man according to his daughter, Lena Luthor, implying that Lionel has a sense of morals and honor, unlike 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.
However, it's strongly suggested that Lionel had a difficult relationship with his son, Lex Luthor, and always favored Lena over him. Even before Lena's birth, Lionel was implied to be emotionally negligent and self-centered in his relationship with Lex, given how he would rather attend to his mistress than comfort his son over the death of his beloved pet.
Lionel had also developed a drinking problem, to the point that it negatively affected Lex's life, making him greatly resentful of his father.
- In stark contrast to all the other adaptations of the character where Lionel Luthor has a full set of long hair, he is shown to be bald just like his son in the show. This implies that Lex Luthor's baldness is an inherited trait and not caused by an accident as generally represented.
- Lionel was the only member of the Luthor family who died, due to Lex's resurrection.
Behind the scenes
- In the DC comics, Lionel Luthor, originally named Jules Luthor, debuted in Superman's Girl Friend, Lois Lane #23 (February, 1961) and was created by Jerry Siegel and Kurt Schaffenberger. In later incarnations, he usually remains unnamed.
- Lionel being an alcoholic is a reference from the DC comics, where in all of his incarnations, except his first appearance and Flashpoint, he is a drunk Kansas farmer who is abusive toward his children.