What was Mr Darling's career?

Mr. George Darling works as a bank clerk. Knowing what he does for a living helps to provide us with a better understanding of his character. Mr. Darling is a practical, no-nonsense, down-to-earth kind of man. When each one of his children comes into the world, George, as ever the banker, carefully calculates how much his latest bundle of joy will cost in terms of upkeep. His grounded nature is a useful element in the story of Peter Pan as it provides a center of stability and sheer ordinariness in the midst of all the swirling magic.
Mr. Darling's strict adherence to the conventions of middle-class Edwardian society acts as a counterpoint to the story's fantastic elements. The culture clash of the two worlds, the world of the everyday suburban existence of the Darlings, and the fabled world of Peter Pan, Captain Smee and the Lost Boys, often leads to amusing consequences, such as when the Lost Boys unceremoniously turn up at the Darling residence looking for a place to stay. George, somewhat miffed at not having been informed of their imminent arrival, nonetheless agrees to let them stay in the drawing room:

"Mind you, I am not sure that we have a drawing-room, but we pretend we have, and it's all the same."

The staid, suburban bank clerk has put aside his previous skepticism regarding the magical fairy world and has allowed an element of fantasy to enter (quite literally) into his front room.