Jefferson adopts a more street-wise manner of speaking when disguised as Black Lightning. This is in keeping with the original comic books, where Black Lightning made use of 70's era slang to disguise his identity.
Though shown to be a villain on the show, Looker is actually a hero in the comics, originally as a member of The Outsiders along with Black Lightning.
This is the first live action depiction of Black Lightning. The character was earlier featured in several DC Comics animated projects, and served as the basis for Black Vulcan in Super Friends (1973).
In DC Comics, Peter Gambi is the brother of Paul Gambi, a supporting character and friend/reformed foe (but not confidante) of the Flash.
Originally developed for Fox, however the network executives decided not to exercise the "option" and passed on the series.