Taken 27th overall in the first round of the 1992 NFL Draft out of Arizona, John Fina became the long-term successor at left tackle for Marv Levy’s championship-caliber offense. Taking over as the full-time protector of Jim Kelly’s blindside in his second season, Fina spent a decade serving as an anchor along Buffalo’s offensive line.

Fina demonstrated integrated leverage, swift lateral footwork, and functional strength. Serving predominantly as the starting left tackle, his primary proficiency was in pass protection; he had the range to establish a wide stance against speed rushers on the edge, while employing effective hand placement to anchor against power rushes, thereby maintaining the integrity of the pocket within Buffalo’s K-Gun passing scheme.

Following his tenure as a primary rotational lineman and special teams contributor as a rookie in 1992—where he participated in Super Bowl XXVII—Fina assumed the role of starting left tackle in 1993. He commenced all 16 regular-season games and three playoff games, including Super Bowl XXVIII, thereby facilitating opportunities for Thurman Thomas and safeguarding Jim Kelly during Buffalo's fourth consecutive AFC championship campaign.

Fina served as the Bills' primary left tackle for nine successive seasons (1993–2001). Renowned for his consistent performance amid evolving offensive strategies and quarterback changes, he provided stability to offensive lines that facilitated 1,000-yard rushing seasons for Thurman Thomas, Bryce Brown, and Antowain Smith.

Fina ended his ten-year Buffalo tenure after 2001, then played his final NFL season with the Arizona Cardinals in 2002. He started 131 of 148 games for Buffalo.