The waiver allows Fields to forgo the usual one-year waiting period for a transferring student-athlete. He is expected to be the front-runner to win the Buckeyes' starting job when spring practice begins in March.
Fields joined Ohio State in January after spending his first semester of college playing for his home-state Georgia Bulldogs. The former five-star prospect threw four touchdown passes and ran for four more while playing sparingly behind starter Jake Fromm last fall.
"I am happy for Justin and his family," Ohio State coach Ryan Day said. "I also want to express my appreciation to the NCAA for its assistance in getting this matter resolved efficiently and with such a positive outcome for Justin."
The NCAA adjusted its policy last spring to make it easier for transferring athletes to find an immediate path to the playing field. The new rules state that a player can be granted a waiver to play right away if he can show "documented mitigation circumstances" that the change of schools was made to better impact his "health, safety and well-being."
"To Buckeye Nation: thank you for your warm welcome. I will work hard to represent you and The Ohio State University in a professional and respectful manner," Fields said in a statement. "My dad always tells me that 'you can't get to where you are going by looking in the rearview mirror.' I'm ready to move forward and embrace the next season of my life."
Fields said he harbors "no regrets" about his time at Georgia. Many speculated that Fields would petition the NCAA for eligibility based on an incident that occurred at a game this past season when a member of the school's baseball team yelled racial slurs from the stands.
In an interview Wednesday, Fields declined to go into detail about the specifics of the case made to the NCAA. He said Friday that speculation and his story "took on a life of its own" over the past month.
"My overall experience at UGA was fully consistent with UGA's commitment to diversity and inclusion," Fields said. "My sister is a softball player at UGA. I am still close friends with many of my UGA teammates. A part of me will always be a Georgia Bulldogs fan."
Fields said he didn't plan to discuss his transfer any further in the future.
The new NCAA rules were immediately put to the test last year by six former Ole Miss players who were granted immediate eligibility to play in 2018. The same attorney who helped those players, Tom Mars, assisted Fields and his family with the process.
"I'm happy for Justin and his family and all the Buckeyes fans who've been waiting for this decision," Mars told ESPN on Friday afternoon. "Justin's not only a great quarterback, he's also an exceptionally mature and impressive young man. He fully deserved to receive a waiver."
Fields joins an inexperienced quarterback group on Ohio State's 2019 roster -- of the four on the roster this spring, none has thrown a pass for the Buckeyes. His top competition for the starting spot is expected to be redshirt freshman Matthew Baldwin.
Fields said Wednesday that he was working daily to learn the Buckeyes' playbook and getting to know his teammates. He said he chose Ohio State after seeing the success that All-Big Ten quarterback Dwayne Haskins had last season and hopes to replicate those record-setting numbers.
"They didn't really have to sell me too much, just going based off what Dwayne did last year and how much success he had in this offense," Fields said. "I felt like I could come in and do the same things that he did."
News of Fields' eligibility boosted Ohio State's odds to win the College Football Playoff National Championship from 12-1 to 8-1 at the Westgate Las Vegas SuperBook.