Ad Age’s annual 40 Under 40 feature is just a few weeks away. Ahead of its publication on Sept. 9, we are asking former honorees to share career advice, including how they got to where they are today. Don’t forget to nominate your own rising stars for this year’s list ahead of the July 22 deadline. You can do so here.

Jen Sey, chief marketing officer at Levi Strauss & Co,  has been at the company for two decades, an unusually long stint in an era where a lot of marketing professionals switch jobs every few years. Back in 2006, when Sey made Ad Age’s inaugural 40 Under 40 list, she was director-consumer marketing, hard at work on a campaign called "A style for every story" and a film integration with "The Sisterhood of the Traveling Pants." 

Sey, who was promoted to CMO in 2013, is today tasked with keeping the 166-year-old Levi's brand relevant with consumers around the globe. Last year, Sey spearheaded a campaign encouraging younger consumers to vote. She's also been ramping up the brand's sustainability efforts. Below, she looks back at her career and shares what advice she would give her younger self. 

What was your biggest career mistake and what did you learn from it? 
I didn’t advocate for myself soon enough. I thought if I just put my head down and do good work, it will get recognized. Not necessarily how it works. And women often don’t advocate for themselves because it feels boastful. We don’t want to come across that way. But if you don’t advocate for yourself you will get overlooked. People will just assume you are happy where you are. 

What piece of advice do you wish you could give your younger self? 
Bring your whole self to work and to what you do every day. If you leave pieces of yourself out of the work place you aren’t operating at your full capacity, with all of your strengths.

What about where you are now do you find most surprising? 
That I’ve been at Levi’s for 20 years. That I’ve been in marketing for 25. I thought this would be a temporary thing.

How many hours of sleep do you get a night? 
Not enough. I have a two-year-old. She comes to get me in the middle of the night to sleep with her in her room – it’s hard to fall back to sleep.

Who is your hero? 
Rachael Denhollander. And the army of survivors who spoke out about Larry Nassar, the USA Gymnastics team doctor who was sexually abusing athletes for decades. At great risk to herself, Rachael spoke publicly first, and the survivors came out in full force to send him to jail. I was an elite gymnast in the 80s and have been outspoken about the abuse in the sport, specifically in my memoir Chalked Up (2008). It takes a tremendous personal toll to speak out and not be believed, to be excoriated publicly. And [to] keep going, to do what is right.