Brown has played 13 matches for the Eagles this year after playing just eight senior matches in 2012.
The 24-year-old said at a media conference on Monday that he was still unsure of his future beyond this season but he was happy to be at West Coast.
The 2006 first-round draft pick confirmed on Thursday that he always wanted to remain at the Eagles.
"I have always loved this club and never wanted to leave," Brown told the club website.
"There is a great feeling in the playing group, my best mates are here, I really enjoy living in Perth and wanted to be a part of the future here.
"Last year I was in and out of the side, played only (eight) games and while I concentrated on playing as well as I could at East Fremantle and enjoyed playing there, I wanted to be playing in the AFL.
"This year I have been playing more consistently at AFL level and it has been satisfying."
West Coast's list manager Craig Vozzo told the club website that Brown was always a required player at the Eagles and they were very keen to re-sign him.
"We have always seen Mitch as a key member of our squad,” Vozzo said.
"That was why we said he was off the table last year when St Kilda was so keen on securing him.
"Mitch is not just an important player, he is a quality person and someone we see as integral to our club and the future."
