I used to be so aggressive, but after a while I started learning. It's not that I know how to adapt, but I know all styles of fighting so I can change my style of fighting to whatever it needs to be. That just comes from years of training and a lot of sparring partners.

Esparza was the subject of Soledad O'Brien's 2011 CNN documentary In Her Corner: Latino in America 2. Esparza has an endorsement deal with CoverGirl cosmetics.

In May 2012 Marlen Esparza qualified to compete at the 2012 Olympics becoming the first American woman to qualify for the Olympics in the first year that women's boxing will be an Olympic event. She was the subject of an extensive profile in the June 2012 issue of The Atlantic which discusses in detail her childhood education and her intense commitment to competition and training.