Smith, the reigning Open and Players champion, was one of six PGA Tour players announced as new signings by the Saudi-backed breakaway circuit on Tuesday, joining Cameron Tringale, Joaquin Niemann, Harold Varner III, Marc Leishman, and Anirban Lahiri.
The Australian is the highest-ranked player yet to make the switch and will make his debut in Boston this week for the fourth event of the inaugural LIV Golf season, alongside the five other new signings.
The 48-man field already includes the likes of Phil Mickelson, Dustin Johnson, Brooks Koepka, Bryson DeChambeau and Henrik Stenson.
As a result of their decision, all six players will no longer be able to participate in PGA Tour events, while Smith is also now ineligible to represent the International Team at the Presidents Cup this September.
CEO of LIV Golf, Greg Norman, said: "LIV Golf is showing the world that our truly global league is attracting the world's best players and will grow the game into the future for the next generation.
"The best and the brightest continue to embrace the excitement and energy of LIV Golf and what we're building: a tangible league for team golf that will connect with new audiences all over the globe. We can't wait to tee off this week at The International and deliver another memorable event experience for fans."
Tringale, who has career earnings in excess of $17million but has never won on the PGA Tour, revealed he was moving to LIV Golf in a social media post on Sunday.
"After much reflection, prayer, and conversations with trusted advisors, I have made the decision to not renew my Tour membership for next year and join LIV Golf," he wrote.
The LIV Golf Invitational Series will become the LIV Golf League from 2023, with 48 players and 12 established team franchises competing in an expanded 14-tournament schedule offering more than $400m in prize money.