During Bomar's freshman season at Vanderbilt, he was already a standout player as a starting fullback. In a game against the Longhorns at the Texas State Fair in Dallas, the Commodores won 20–0 after they were expected to lose by two touchdowns. Texas had been undefeated in 1920, winning the Southwest Conference. The 1921 squad was considered possibly the best in Longhorns history, and Vanderbilt football seemed to be in decline when Georgia Tech defeated the Commodores 44–0 the previous year. Dan McGugin gave a speech invoking late former Vanderbilt quarterback Irby Curry before the game. According to Edwin Pope's "Football's Greatest Coaches", "The Texas game, sparked by McGugin's unforgettable oratory, was the big one; and Vandy got out of the year without a loss." Bomar scored on a 40-yard interception return for a touchdown in the fourth quarter, increasing the Commodore lead to two touchdowns. In the sixth game of the season, Vanderbilt defeated the Alabama Crimson Tide 14–0 at Birmingham. The victory was expected by insiders (then often called the "dope"), with Vanderbilt favored by two touchdowns. Early in the first quarter several runs by Jess Neely, a long pass from Neely to Tot McCullough and a 17-yard run by Neely brought the ball to the nine-yard line. After a run by Frank Godchaux, Bomar bucked over the line for a touchdown. The game against the Georgia Bulldogs decided the Southern Intercollegiate Athletic Association (SIAA) championship that season, with Bomar excelling at linebacker. "Georgia would have trampled Vanderbilt to atoms but for Lynn Bomar," wrote "Nashville Tennessean" sportswriter Blinkey Horn. "Lynn Bomar was the stellar performer of the game. In the first-half he made two-thirds of the tackles", and reportedly prevented five Georgia touchdowns that day. The Commodores tied the Bulldogs 7–7 on a fourth-quarter onside kick for a share of the SIAA title, finishing the season with a 7–0–1 record.