Lex Luthor hates Superman. It's just a fact of life. So why would he, in Final Crisis, decide to team up with the Man of Steel?
The answer is relatively simple. In the long tradition of DC crises, Final Crisis - Grant Morrison's discombobulating epic that involved Darkseid acquiring the Ant-Life Equation and cosmic vampires - threatened to destroy the entire universe, and Lex Luthor, obviously fond of having a universe to exploit, and not particularly willing to take orders from others, was not overly fond of the concept, and so decides to become a mole within the Secret Society in order to thwart Darkseid once and for all.
He takes on Libra - Darkseid's prophet - stops the Anti-Life Equation from being spread and then joins Superman in battle against Darkseid's hoards. This earns him a nice little PR boost, before he goes along with the plot to recreate the universe without Darkseid by using the Miracle Machine.
Lex has of course dabbled with heroics afterwards, but you won't find a better example of him using his powers for good than Final Crisis.
WhatCulture's very own resident movie guy, Ewan has been working in the content creation biz for over 10 years now, having started as a freelance contributor to WhatCulture Gaming all the way back in 2015. After graduating with a First-Class Honours in History from Northumbria University in 2017 (where he won a prize for a totally killer dissertation on the Watergate years), Ewan took on the role of Comics Editor at WhatCulture and quickly developed WhatCulture Comics into one of the biggest superhero-focused channels on YouTube. He followed this with a brief hiatus at Screen Rant in 2021, where he worked across the Gaming and Film sections as a writer and editor, before returning to WhatCulture as a Senior Content Producer / Presenter in 2023. He started his own podcast, We Love Dad Movies, in 2022, and has contributed several written pieces to the Eisner-nominated comics website Shelfdust as well.
In his current role, Ewan incorporates his love of cinema, comic books, and history into written pieces and video essays for WhatCulture's Film & TV channel, as well as WhatCulture Gaming and WhatCulture Horror, with a particular focus on nineties-era Dad Movies, old school Westerns, and Golden Age Hollywood Noir. John Carpenter is his fave, and he thinks Batman Beyond should never have been cancelled. If that's your vibe, you'll probably like his stuff.