Alexander Joseph Luthor is the CEO of his company LexCorp, which he gained the funds for out of an attempt to get a huge life insurance policy from his parents' death. As such, he excelled in designing aeroplanes and space shuttles. When Superman came around, Lex became enamored but also enraged at him for knowing of someone like a Superman becoming a huge liability for Metropolis. As such, he went at odds with the Man of Tomorrow, getting around the moral that power comes from pure skill and smarts rather than godlike powers. Luthor's even responsible for creating well-known Superman villains like Bizarro, and even discovering a hunk of Kryptonite and fashioning it into a ring just in case. 

While many of his antagonistic traits with the Justice League remain present in the Primeverse, he is best friends with Superman in the Injustice universe, and has never engaged in law breaking. Unbeknownst to the Man of Steel, he secretly supports and funds Batman's insurgency to topple the Regime.

For the voice of this character, you will need to refer to Clancy Brown's performances of the character in the DCAU. In the Primeverse, a more sinister tone will need to be present, while a somewhat lighter tone needs to be used for the Injustice version, or something similar to the performance by Mark Rolston.