- "I loved your father. I regret that I never told him so. I regret that I didn't help him more."
- —Lucius Fox to Bruce Wayne[src]
Working with Thomas Wayne
Helping Bruce Wayne
Lucius entered during Bruce Wayne's discussion with Sid Bunderslaw to retrieve Bruce. Before allowing him to leave the company, Lucius told Bruce that his father was very guarded man, a stoic, who hid his best self from the rest of Wayne Enterprises.
Bruce's butler Alfred Pennyworth went to visit Lucius at a bar to make sure he was trustworthy. When making sure he could trust Lucius, he asked him to help fix a computer he smashed up which contained vital information on Wayne Enterprises. Lucius begins working on the computer, which is hidden in a secret cave at Wayne Manor which Thomas had previously used before he was killed.
After fixing the computer Lucius came out of the cave to inform Bruce only to find he is missing, having just been kidnapped by Theo Galavan. When Alfred, alongside Jim Gordon, Harvey Bullock, Selina Kyle and Oswald Cobblepot and his gang head to Theo's apartment in order to rescue Bruce from being killed by the Order of St. Dumas, Lucius informs Captain Nathaniel Barnes on what is happening. Bruce is eventually rescued thanks to the team up, with a lot of the Order of Dumas members killed.
Lucius informed Detectives Gordon and Bullock that Wayne Enterprises manufactured liquid helium. He then told them that for years it was used as a part of their cryogenics program, but Thomas Wayne shut the program down along with a few others.
Lucius sat down in Thomas Wayne's lair and got up to go and eat when Alfred arrived telling him and Bruce he had prepared a meal. Bruce then tells the two what he found on Thomas' calender. Lucius later arrives at Wayne Manor with an important discovery after having sought scientists who had worked for Wayne Enterprises cross-referencing the words "Pinewood" and "philosopher". To the astonishment of the group, Fox showed them a photograph of the old Gotham cricket team where Thomas stood by his friend Hugo Strange, otherwise known as " The Philosopher".
At Wayne Manor, Alfred berates Bruce for involving Selina, who was now in danger because of him. However, Lucius and Gordon decided to use this opportunity to infiltrate Arkham Asylum and find the secret laboratory where Hugo Strange was creating monsters. Given that, and despite Alfred's protest, Bruce decides to accompany Lucius announcing that he'd ask for a tour as the Wayne foundation gave the Asylum money every year. Outside, Strange meets with Lucius and Bruce, and Bruce asked for a tour. He then told Strange that he wanted to talk with him, while Lucius look around, and Strange he offered Ms. Peabody as his guide. Lucius then agreed and using the excuse of going to get his coat, let Gordon out the trunk in his car, telling him that if he saw anything suspicious he would mark it with white chalk. Lucius was given a tour of the facility by Ms. Peabody, and Lucius activated his Geiger counter that he had designed to find the location of the Indian Hill facility. Lucius continued his tour of the facility though Peabody catches him with the Geiger counter, however, he excuses it as a device that measured the air quality. Soon after, Lucius finds the entrance to the Indian Hill facility and marks the wall with white chalk before continuing with Ms. Peabody. Soon after, Lucius was grabbed and taken into a room with Bruce. From the control room outside, Nygma announced his presence and told Lucius and Bruce that Strange had tasked him with finding out how much they knew about what Strange had been up to, and who they had told. He then informed them that if they didn't, poison gas would spill from the nozzles above their head, and kill them. Lucius was then able to identify Nygma through his voice, and Nygma gave them five minutes on a timer to answer before the gas was activated. Lucius and Bruce then banged on the door for help.
Lucius and Bruce were at the mercy of Edward Nygma, who tries to find out everything they knew about who ran Indian Hill. Lucius suggests the answer to Nygma's question was Hugo Strange, though Bruce gave the answer of Wayne Enterprises, which was correct. Nygma then asked them who ran Wayne Enterprises. On the other hand, Lucius and Bruce give an incorrect answer about who ran Wayne Enterprises, and Nygma activates the poison gas, laughing as the two fell unconscious. Both Lucius and Bruce later wake up in the same room as Jim. They are later freed by Selina, and Lucius accompanies Jim to the basement to disarm the bomb Hugo Strange had activated. At the bomb site, neither Gordon or Lucius had an idea of how to defuse the bomb. Elsewhere, several patrol cars sped to Arkham and Fish continues to drive the bus. Lucius and Gordon aren't able to manage to come up with an idea on how to diffuse the explosive until suddenly Peabody regains consciousness and tells them "water." After Gordon pours water in the bomb's circuits disabling it, Lucius and Gordon realize afterward she meant water for her to drink.
Working for the GCPD
After the escapes of the inmates from Arkham Asylum, Lucius quit his job at Wayne Enterprises, because it was morally corrupt. He then started at the GCPD as expert for the escapees.
- High-level intellect: A former executive of Wayne Enterprises, Lucius is very intelligent. He is even able to figure out and understand Edward Nygma's riddles.
- Expert scientist/Forensic expert: Despite the fact that he has only been a member of Gotham City Police Department, for about a short amount of time, Lucius has proven himself to be an excellent scientist and forensics examiner.
- Martial Artist: Having taken night classes, Lucius is now a black belt in the fighting style of Jiu Jitsu.
- Lucius Fox debuted in Batman #307 (released on January 1979) and was created by Len Wein and John Calnan. In the DC comics, he runs Wayne Enterprises on Bruce Wayne's behalf and is one of a few people who knows that Bruce Wayne is Batman. He is also a engineer who created most of Batman's gadgets.
- In "A Dark Knight: A Beautiful Darkness", Lucius reveals that he is a black belt in Jiu Jutsu, having taken night classes.
- In the episode A Dark Knight: That's Entertainment, Lucius Fox helps create a device meant to jam a remote detonator that will trigger four separate collar bombs. This parallels and possibly homages his role in The Dark Knight Rises film where he also develops a jamming device to block a bomb from going off.