Michael Caine has revealed how he came up with his very own back story for Alfred in The Dark Knight trilogy. Michael claims that, since the writers never gave Alfred a back story, he decided to make one up for himself.

Michael Caine smiles for the camera
Caine explained, “I played the butler, so you haven't got some great backstory for the blooming butler. But I invented a backstory, which is Bruce's father went to the SAS headquarters in Herefordshire to see an officer friend.”
He added, “He was in the officer's mess and there was a sergeant there who had been badly wounded and couldn't go back to the war and didn't want to go into Civvy Street, so he took charge of the sergeant's mess, and that's me.”

Michael Caine as Alfred
Michael continued, “So what that is is you have this very tough ex-SAS guy who knows all about drinks and service and getting sandwiches and coffee, because he had to learn it for the sergeants mess. So I told [Christopher Nolan] that story and he said, 'oh, I should have written it'. Actors always invent a backstory if the writer hasn't.”
Michael Caine has obviously still got a soft spot for the role that he played in all three of Christopher Nolan’s Batman movies and he has even confirmed that he is interested in a small cameo in the Justice League movie.
The Dark Knight trilogy