Brandon Molale as Shazam/Captain Shazam
An actor cast for mostly physical roles, this will be no different. The guy looks like he born as Cap and then turned into a human. Molale is a fan-fav to play Shazam and I feel he will be great in this role, Billy gained his power Billy, a homeless newsboy, is led by a mysterious stranger to a secret subway tunnel. An odd subway car with no visible driver takes them to an underground tunnel with seven statues depicting the Seven Deadly Enemies of Man (Pride, Envy, Greed, Hatred, Selfishness, Laziness and Injustice): the lair of the wizard Shazamo. The wizard shows that he has observed the hardship of Billy's life, and grants him the power to become the adult superhero called Shazaml, just before a stone suspended above Shazamo's head crushes him. His ghost says he will give advice when a brazier is lighted.
Griffin Gluck as Billy Batson
A young boy granted powers by the wizard Shazamo. Everytime he utters the phrase "Shazam" he is struck by lightning and transforms into the superhero known as Shazam.
John Malkovich as Shazamo the Wizard (Often just called 'The Wizard)
An ancient wizard who has been using his powers for many centuries to fight
the forces of evil, but that he is now old and not long for this world. He therefore passes along part of his power to Billy, who shouts the name given to him, Shazam, to transform into said superhero. Billy can summon the ghost of Shazamo for guidance by lighting a special brazier in his lair (the Rock of Eternity). His parting words to Billy were "Fear Black Adam".
Dwayne "The Rock" Johnson as Teth Adam/Black Adam
Another fan-favorite choice The Rock has proven his acting chops as well as impressed with his muscular figure.
Black Adam was a corrupted, Ancient Egyptian predecessor of Shazam who fought his way to modern times to challenge Earth's mightiest heroes. He has been proven a foil to Shazam, Superman and many others. Ideally he would get a post-credits scene in a DC film to explain or even allude to this origin considering it could be slightly foolish to explain his whole origin in one take. When Teth Adam ays the magic word "Shazam", he is transformed into Black Adam and granted powers derived from ancient Egyptian gods.