The Unexpected Way Cassidy Montalvo Became Social Media’s Most Trusted ‘Big Sister’

In a digital landscape packed with perfectly curated aesthetics and influencer highlight reels, Cassidy Montalvo has carved out something different, a safe corner of the internet built on sisterhood, softness, and honesty. With more than 3.8 million combined followers hanging onto her “big sister” advice, Cassidy isn’t just a creator people watch; she’s someone they trust. But as she tells The Blast, the “big sister of the internet” persona wasn’t a strategy. It wasn’t planned at all. It’s simply who she’s always been.

“I grew up with all sisters. I actually come from a family with six girls,” she shared. “So I'm a big sister and I have big sisters. It’s just all I've ever known. I've never known a life without being a sister and having sisters.”

That lifelong role became the blueprint for the creator she is today. But Cassidy didn’t recognize the impact of that sisterly energy until strangers began telling her how much they needed it. “I didn’t ever think about the fact that other people won't have that,” she said. “When I was starting to get DMs and comments was really when I realized, okay, everything I share in my sister group chat or that my sisters have taught me… I’ll just share with everyone else for those who never had this.”

Once the messages started pouring in, followers thanking her for teaching them things they “never learned," the purpose behind her presence became clear.

In an era where “authenticity” often gets reduced to a buzzword, Cassidy keeps it grounded. “Oftentimes authenticity is just another word for being human, just showing your human parts,” she said. “I’m absolutely the farthest thing from perfect. My laundry room is usually full. I am on anxiety medication. Life is not perfect and it's not supposed to be.”

Her philosophy is simple. People don’t need a perfect example to look up to, but just a real one. “You don't have to be above other people to be an example,” she explained. “You just have to come alongside them.” That approach has resonated deeply with her audience, especially young women who say Cassidy makes them feel understood, not judged.

Cassidy doesn’t plan elaborate editorial calendars or chase trends. She listens. “A lot of what I share comes from my comments,” she said. “I'm in my comments, my DMs all the time. That’s the number one place I get most of my content ideas.”

Her TikTok and Instagram strategy is all about her community. When they ask, she answers. Often, the ideas come straight from her real-life sister group chat. “If one of my sisters has something happening, they'll ask me,” she said. “So if they ask me something and I'm like, ‘Wait, that’s a great tip to share,’ then I’ll just take my sister group chat to TikTok.”

Her social media platforms, she says, function almost like “a running sister group chat, just sharing it with the world.”

The creator says her audience connects with the parts she once worried might be “too real.” “Showing up messy and learning with my audience and growing and making mistakes is really what people are gonna connect with,” she explained.

That vulnerability includes everything from anxiety medication to chaotic closets, the same kinds of confessions sisters would share late at night over FaceTime. And the relatability is intentional in the best way, not curated, not performed, but simply lived.

For thousands of followers who didn’t have sisters, or didn’t have close ones, Cassidy has become the voice they wished they’d grown up with. Everything she shares, from beauty advice to emotional encouragement, comes from the same place she offered guidance to her own sisters growing up. “I love to help my sisters as much as I can,” she said. “And realizing other people don’t have that… that’s when I realized what I could give.”

What she gives is comfort, courage, and connection, the kind beautiful enough to feel like real family.