In Storm Front, Marcone is an established underground boss with construction, gambling rackets, drugs and presumably, prostitution. Harry Dresden is Chicago's only practicing wizard and a consultant for Chicago Police Department's Special Investigations unit. On Dresden's way back from consulting on a crime scene where one of Marcone's henchmen was assissinated using magic, Marcone swoops down in his limo, picks up Dresden and takes his measure in a soulgaze without flinching and tries to warn him off the case.
This doesn't strike me as the actions of someone who is completely ignorant of magic.
First, iron-hearted or not, a soulgaze is supposed to be a moment of shocking intimacy.
Second, the reader is ignorant that Tommy Tom is involved with Victor Sells' rituals to create Three-Eye at the point where he's dead and introduced as one of Marcone's henchmen.
Dresden shuts down Sells, who dies in the process and cannot turn witness or testify to the White Council or the Chicago PD who else was involved in the Three-Eye ring.
In Fool Moon, Marcone's business partner and one of his henchmen wind up dead at the hands of a werewolf.
Harry, while talking to a demon for information on the Loup-Garou, guess that Marcone has his hands on a pack of werewolves. There are only two werewolf packs in Chicago, the Alphas, who would never work for Marcone, and the Street Wolves, a gang of lycanthropes, humans possessed by wild spirits.
Then Marcone, dues to shady business dealing winds up in the crosshairs of the Loup-Garou.
In book 5, Death Masks, John Marcone pops up again after being missing during Grave Peril and Summer Knight. Marcone has Miss Sigrun Gard at his beck and call as a bodyguard. Later, Marcone gains possession of the Shroud.
Does this strike anybody as the actions of a man who is introduced to the reality of magic in Storm Front? I think there's backstory on Marcone that we don't have yet, but he was already looking for a way to exploit magic for his own prestige and power.