Bale revealed to GQ Australia that Batman Begins, The Dark Knight and The Dark Knight Rises have been among the most challenging films of his career.
"I have been deeply honoured to inhabit this character. It was a massive undertaking. Physically, emotionally, every way," the actor admitted.
He also said of filming the end of Nolan's Batman saga: "Suddenly we were in the final throes. I sat down and asked for a little space. I stared at the cowl for a good long moment and thought, 'Man, this one really took on a life of its own'."
Bale recently said that he believes The Dark Knight Rises will be "the last" film in the series, but added that he remains open to further movies.
Last week, the actor reflected on his character Bruce Wayne by suggesting that Batman's dedication to fighting crime has led the hero to miss out on life.
The Dark Knight Rises, co-starring Anne Hathaway and Tom Hardy, opens in the UK and US on July 20.
Watch the trailer for The Dark Knight Rises below: