That's why he's holding 25 campaign events before Tuesday night.
Eyewitness News spent the morning with De León at La Parilla restaurant in Boyle Heights.
"The whole vote by mail, one month early really hasn't taken in these communities, and that's why we're out there everywhere engaging with voters," he said. "We kind of had a feeling that the vast majority of Latino voters would be voting the last week."
De León doesn't have the financial advantage of developer Rick Caruso and is trailing behind him and Congresswoman Karen Bass in the polls.
However, with Los Angeles being more than 50% Latino and having success in housing the homeless in his district, De León isn't giving up.
"I wasn't born with silver spoons in my mouth," he said. "I wasn't born into wealth and privilege. It's because of my mother's strong work ethic I am who I am today. That's why you fight until the last day."
On Friday, Tesla CEO Elon Musk endorsed Caruso on Twitter, saying, "Los Angeles is fortunate to have someone like Rick Caruso running for mayor. He's awesome."
With mass shootings on the rise and the nation debating gun control once again, De León is highlighting his work, taking on the National Rifle Association in this new ad.
Bass also said she'll take on gun control if elected mayor.
She visited the San Fernando Mom's Demand Action group in Woodland Hills on Friday.
On National Gun Violence Awareness Day, the group held a diaper drive for the local domestic violence shelter, Haven Hills.
"The big thing that we need to do is really increase people's awareness about the red flag laws, because we actually have them, but they're way under-utilized, and so that's one of the things that I want to do," said Bass. "We also have an increase in homicides, especially in South L.A., and the majority of those homicides are related to gun violence. About 50% of them are solved. So we have to do deal with that to make sure they're solved and do anything we can around ghost guns."
De León hopes voters are waiting to vote in person.
If you're one of those who would rather not vote by mail, an additional 522 vote centers open in L.A. County Saturday through Tuesday.
To find a polling place near you, click here. For everything you need to know about Tuesday's primary election - including online candidate statements and other election resources - click here.