Zac said in his video, "Alright, yo, 11 years sober [on August 30]. I'm super grateful. I feel very loved. The beautiful notes and messages, thank you so much for all of that."
"As I sit here and I reflect on the past 11 years of my life, I can't help but recognize that actually this has nothing to do with me," he continued.
"This has to do with the people that paved the path for me, those that came before me and, more importantly, the person that is out there still struggling today -- struggling with their addiction, struggling with their mental health, feeling like they cannot go on."
Zac, 38, said people come up to him "all the time" and ask how he stays sober and still has fun.
"I laugh because I've been given this next level existence that I am so proud of," Zac shared.
"Hard was being out there on the street, being willing to die to get high one more time, for one more hit. This life is easy and it's beautiful and it's available to you if you want it."
Zac urged anyone battling alcohol or drug addiction to "ask for help."
"We are here for you, we love you, keep going, dig in. I promise you it gets better. If I can do it, you can do it. Let's go!" Zac concluded.
According to a report the Reading Eagle published at the time, Zac spoke at a gathering at Alvernia University in January 2014 and detailed the extent of his former addiction.
Zac apparently once complained of a pain in his side and asked doctors to remove his gallbladder so he could have access to heavy painkillers. He was also thrilled to receive drugs after a brain tumor was removed from his head.
The report says Zac snorted and smoked OxyContin, shot heroin intravenously, smoked crack, and did "whippets," which is inhaling bursts of nitrous oxide for a short-lived high.
Zac was eventually arrested for possession of crack and driving while intoxicated.
Zac said on The Bachelorette that he hit rock bottom in 2011 when he attempted to cash a forged check from his father's account. Instead of calling the police, the bank teller, Rhonda Jackson, called Zac's father.
Zac said his addiction resulted in "15 years of lying" and culminated with a four-and-a-half month stint at an addiction-recovery facility that helped him turn his life around.
Zac decided to never look back on his bad choices and habits, and in 2017, he co-founded a recovery program with a variety of services called Release Recovery with his friend Justin Gurland to help people reclaim their lives after struggling with addiction.
Zac eventually thanked Rhonda publicly in 2020 for having saved his life.
"In a world that is filled seemingly with so much apathy, Rhonda Jackson taught me a valuable life lesson," Zac wrote in part on Instagram at the time. "Always treat people with love, always believe and always do the right thing. You never know whose life you might be saving."
"Thank you, Rhonda for saving my life," he added. "There are no coincidences."
Zac proposed marriage to Tayshia Adams at the end of her The Bachelorette season, which filmed in August 2020 and aired on ABC in December of that year. Tayshia decided to move to New York City to be with her man, but she also kept her own place in California.
"I still want marriage and to start a family more than anything... [I'm] waiting to be in a healthy supportive relationship while simultaneously being a successful woman; a cohesive unit, not one or the other," Tayshia told a troll in the comments of one of her Instagram posts.
She added, "I want to build an empire, I want to go after my dreams and I want my partner to be supportive of that as they follow their own dreams as well. I want a relationship where we cheer each other on. None of that has changed."
After Tayshia slammed the troll for confusing her focus on her career with putting marriage on the back burner, she wrote, "Maybe applaud me for not settling, staying to true to myself, going after my dreams and working on myself in the interm to be the best version of me for the right person."
Reports recently swirled that there is no bad blood between Tayshia and Zac, and back in June, Zac confirmed that's the case by defending Tayshia on social media in light of negative comments about their breakup.
"Enough is enough. One of the problems with social media is it gives people like you a voice and unwarranted power. The truth is, we see this sh-t, I see this sh-t. It is hard to avoid and it is just not nice, especially when you have no idea what you are talking about/you just make sh-t up," Zac snapped at a fan, according to People.
"I struggle to see why you would be mean for no reason, being kind is so much easier, I promise... So @tayshia f-ck the noise and keep doing your thing."
Prior to starring on The Bachelorette 16 in 2020, Tayshia competed on The Bachelor's 23rd season, which aired in early 2019.
Colton Underwood eliminated Tayshia during his round of overnight Fantasy Suite dates.