Fine, who is one-quarter Cherokee, grew up in Peggs, Oklahoma. According to a 2020 story by Yahoo Sports journalist Jeff Eisenberg, Fine's development as a quarterback began in the summer before his sixth-grade year, during which he attended a quarterback camp at the University of Oklahoma. The young Fine paid special attention to former Oklahoma star quarterback and then-current Sooners assistant Josh Heupel, observing Heupel's throwing motion and paying attention to the advice he offered. During each day's drive home from the camp, he wrote down what he had learned. After the camp, Fine and his father Dale typed up the notes, and he went so far as to place a printed copy next to his bed. Fine was initially trained by his father, who had never played football at any level. Each day, the two would teach one another proper throwing motion via the notes they took at the aforementioned camp. In Eisenberg's story, Dale recalled, "It was hours and days and months and years of repetition. The motto we went by was that it wasn’t just practice that made perfect. It was perfect practice that made perfect." By the time Mason finished his eighth-grade year, they no longer worked on his mechanics. The following summer, he attended a quarterback camp at which an instructor praised his throwing motion and asked about his quarterbacks coach. Eisenberg noted, "The instructor couldn’t believe it was his dad, let alone that Dale Fine had no previous football experience."
High school
Since his hometown of fewer than 1,000 operated only a K–8 school, Fine had a choice between several nearby high schools, and enrolled at Locust Grove High School in Locust Grove in 2012. The Pirates had just hired a new head coach Matt Hennesy after winning only two games in the previous three seasons. Eisenberg noted that the new coach had to make a decision regarding his new talent—while Fine was the team's best passer, "Hennesy feared putting a 5-foot-9, 135-pound freshman behind a patchwork offensive line." Hennesy decided to start Fine as a wide receiver, but designed a series of trick plays to utilize Fine's throwing ability; Fine threw for more than 600 yards as a freshman despite not playing quarterback. He went on to start at quarterback in his remaining three high school seasons, setting the all-time Oklahoma high school record for passing yards and touchdowns and becoming the first player to ever win the state's Gatorade Player of the Year award twice.
Recruitment
Despite his gaudy high school statistics, Fine finished his senior season without a single scholarship offer, largely due to his lack of size. During a summer camp before his senior season, an assistant for Arkansas State pulled him aside, praising his arm strength and ability to escape a collapsing pocket. However, he then told Fine that his small size made it unlikely that he would ever play at a Division I FBS school, instead offering to recommend him to Division I FCS or Division II schools. Fine would tell Eisenberg, "I was polite and told him that I appreciated it, but inside I was fuming." This coach was not alone in his sentiment; Fine went without an offer even after sending out numerous highlight tapes and attending camps at four other FBS schools. Rice showed strong interest after Fine's junior season, but went with a considerably taller prospect; Oklahoma State recruited him only as a walk-on, and did not make him an offer even after its main quarterback target rescinded a verbal commitment to the school; and when Hennesy called Kansas State'sBill Snyder about Fine, Snyder responded that he didn't recruit quarterbacks under 6 feet tall. Fine caught a break when North Texas hired Seth Littrell as head coach shortly after the end of the 2015 season. Littrell, a former Oklahoma player who grew up in Muskogee, Oklahoma, was a close friend of Hennesy who operated an Air Raid offense similar to the one that Fine quarterbacked at Locust Grove. Shortly after his hiring, Littrell called Hennesy to ask about available quarterbacks; while North Texas had an incoming graduate transfer from Alabama for the 2016 season, Littrell sought a future prospect. Littrell and his staff were sold on Fine's ability; he would tell Eisenberg, Sensing that this was his best chance at an FBS offer, Fine made makeshift lifts for his shoes in order to appear taller for his North Texas visit. For his part, Littrell would say, "He could have shown up in combat boots with four-inch heels and we’d have taken him." On February 3, 2016, Fine signed a National Letter of Intent with North Texas.
College career
North Texas
2016
Fine started nine games for North Texas as a true freshman in 2016, throwing for 1,572 yards and breaking the school record for longest play from scrimmage with an 80-yard touchdown run against UTSA to earn a spot on the Conference USA All-Freshman team
2017–2018
Over his sophomore and junior years, Fine led the Mean Green to 9 victories in each season and threw for a total of 7,845 yards and 58 touchdowns. He earned back-to-back CUSA Offensive Player of the Year awards and broke the school's career passing yards record along the way.
2019
Going into Fine's senior season in 2019, he was named as the top college quarterback in Texas by Dave Campbell's Texas Football and received national media attention for the Heisman campaign started on his behalf by the UNT athletic department.
