The phrase "making of a man" refers to the process by which a man becomes successful or prosperous, while the phrase "made man" refers to actually being successful.
The phrase "making of a man" is used when Henry discusses Harris’s "humble feeding house." He says, "I was the making of Harris. The fact had gone all abroad that the foreign crank who carried million-pound bills in his vest pocket was the patron saint of the place.” When people find out that Henry, already known for having a million-pound bank note, breakfasts at Harris’s eating house, the restaurant’s popularity skyrockets. Earlier, Harris’s eating house had been "poor, struggling," but it became "celebrated, and overcrowded with customers" after London society hears that Henry eats there.
The phrase "made man" is used when Henry is caricatured in Punch. He says, "Punch caricatured me! Yes, I was a made man now; my place was established. I might be joked about still, but reverently, not hilariously, not rudely; I could be smiled at, but not laughed at." Because he was mimicked so publicly, Henry becomes famous, and his good reputation is solidified.
