In July 2015, Madison released her first book and memoir, Down the Rabbit Hole: Curious Adventures and Cautionary Tales of a Former Playboy Bunny.To afford her college tuition, Holly competed to become a Hawaiian Tropic model and worked as a waitress at Hooters.Her appearance at these venues led to invitations to the Playboy Mansion and at the age of 21, after more than a year of such visits, Madison asked to move in.

Holly is most widely recognized for her role in the E!

hit reality television show, The Girls Next Door and for her own series, Holly's World.

"It's all good-natured and not mean like other reality shows," Madison said of her show.

"I'm really excited about the new series because I am also getting a legitimate co-producer credit for all the work I do behind the camera. I'm super excited to learn from the best and take on new responsibilities." In 2015, her memoir Down the Rabbit Hole: Curious Adventures and Cautionary Tales of a Former Playboy Bunny (ISBN 978-0-06-237210-9) was published.

During seasons three and four, Madison was shown working at the Playboy studios as an intern and later a junior photo editor.

She also helped design and put together The Girls Next Door 2007, 2008, and 2009 calendars.

However, during an interview at the Playmate of the Year luncheon in May 2008, Hefner stated, "I love Holly very much and I think we're going to be together the rest of my life, but marriage isn't part of my puzzle. Girls Next Door was a great place to start but it was somebody else's show.

It's not a personal thing; I just haven't had much luck with marriages." In 2009, Madison stated, "I'm never dating anybody again. I'm really happy with myself and being with my friends...

In May 2016, Holly released her second memoir The Vegas Diaries: Romance, Rolling the Dice and the Road to Reinvention (ISBN 978-0-06-245705-9) which debuted on The New York Times Bestseller list.