'Imposters' ' Parker Young Married Longtime Love Stephanie Weber in Intimate Ceremony: 'Amazing Day'

After 16 years together, Parker Young and his longtime love, Stephanie Weber, recently took a big step forward in their relationship.

PEOPLE can exclusively reveal that Young and Weber quietly wed in September 2021 in a private backyard ceremony held at their California home.

The 33-year-old actor's United States of Al costar Adhir Kalyan officiated the intimate ceremony, which commenced on Weber's birthday.

The two high school sweethearts previously got engaged in March 2018 and later welcomed their daughter, Jaxon Orion, that July.

Ahead of the big day, Young wanted the romantic occasion to be a "surprise" his wife "would never forget."

"We've been together for 16 years — since we were kids," the actor tells PEOPLE. "I think when couples have been together for as long as we have it can be easy to get complacent and let the spark can fade. It's important to keep things exciting."

In planning the pair's low-key nuptials, Young says he "never had any doubts" how Weber would react to the concept of a surprise wedding.

"We never really cared to have a fancy, showy, expensive wedding," the Imposters alum says. "All we need is each other. That's all we've ever needed. We committed our lives to each other long ago, so really this was just semantics."

Weber admits she was "absolutely in shock" by Young's surprise wedding plans.

"It was my birthday and I'm in, basically, PJs and no makeup. Parker keeps asking me to get ready and I'm like, 'Why? We have no plans!'" she recalls. "And so Jaxon, our daughter, comes up to me and says 'Mommy, put mascara on,' which is pretty common for her to say. She loves when I have mascara on. I didn't think anything of it and put some mascara on. Then a few mins later she comes in and asks me to put my birthday dress on. At this point, I'm like, 'Okay, something fishy is going on.' But never did I think we were going to get married!"

She continues, "Shortly after I get my birthday dress on, the doorbell rings and I'm like, 'Who is this?' I open the door and a man in a suit and briefcase is standing there and I was a bit confused but immediately started crying, and said to Parker, 'Is he here to marry us?'"

From there, Weber says the pair began "filling out the papers and signing Parker's life away" as well as her maiden name.

"The doorbell rings again and I'm thinking maybe family is here. I opened the door and its Adhir, Parker's costar from U.S. of Al," she continues. "I'm like, 'WTF,' at this point. He says, 'I'm going to officiate your wedding.' And of course, I started crying again. At this point, it feels like a dream. Literally, the man that I have been together with for 15 years is finally caving in and giving me my daughter's last name."

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"So we go out in our backyard and we have a mini ceremony with just Jaxon, [our dog] Stella and our babysitter, who just showed up for her shift and was also very confused," she adds. "I guess she was our witness."

For Young, "the commitment two people make to each other" is "what matters most" to him.

"I had already made that commitment to Stephanie almost two decades ago when I met her in high school and asked her to be my girlfriend," says Young. "We didn't need any paperwork or documents to solidify our commitment or some grandiose event to make it official. I found my soul mate long ago and we determined to walk this life together hand in hand. Maybe one day we'll throw a big party to celebrate, but until then we're officially married!"

The small gathering "was perfect," says Weber.

"I've always wanted to elope and just go to the courthouse and get married. But to be doing it with my little family and with Adhir officiating it in our backyard, I couldn't have asked for a better way to get married," she adds. "With that said, I'd still like to have a bachelorette party and a big party — or a mini wedding — to celebrate. But I'm just waiting for this COVID nightmare to subside a little."

And the ceremony went better than Young could have imagined as well.

"We had the most amazing day — just us and our daughter," Young concludes. "It was certainly a moment that we will cherish and remember for the rest of our lives.