The past two seasons have been turbulent for Casillas, who fell out with previous coach Jose Mourinho, before finding himself out of Carlo Ancelotti's Liga XI for much of last season.
Casillas has been in the headlines again this term, having fallen out with full-back Alvaro Arbeloa and he also received jeers from Real fans after starting the season with perceived below-par performances.
But, having seemingly regained Ancelotti's trust and regained his spot in La Liga, Casillas is now determined to see out his career as a one-club man.
"Yes, I had thought about leaving," he explained to Canal+.
"You do not want to disturb things or create a bad environment because you always want Madrid to win.
"But then you think 'you have to compete and fight'. These last two years have seen me fight and seen me struggle.
"There were no offers for me and I want to finish my career here."
Casillas also discussed the pain he felt at his public criticism, at its worst in last month's derby defeat to Atletico Madrid.
He added: "It hurts. I have been here since I was nine years old, I have got many things with this club and it has been a springboard to the national team for me.
"The public are free to do what they want but it also hurts. Being here so long also means I have to accept certain things."
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