After Fenway Park's inaugural Red Sox championship season concluded, the turf at the ballpark converted to gridiron.  On November 30, 1912, the ballpark hosted the National High School Football Championship Game, where Oak Park High School of Illinois beat local Everett High School by a score of 32-12.  Boston Latin High School and Boston English High School also played a late-November football game in 1912. 

In the 1920s, as the Red Sox fortunes slipped, Fenway Park became a prime venue for high school and college football in Boston,  including a rare tripleheader of three football games on November 24, 1927.  The next season, wooden bleachers were installed in left field for the first time, and the Boston College Eagles began playing some of their games there that fall. 

In 1933 the NFL's Boston Football Braves moved from Braves Field, changed their name to the Redskins, and called Fenway Park their home.  They would not be there long because in 1937, they moved to Washington D.C. where they still reside.  However, Boston College, Boston University, and Holy Cross all played some of their home football schedules at Fenway.  In 1940, Boston College's football team played all their home games here on the way to an undefeated season and a victory in the Sugar Bowl. 

During World War II, the Chicago Bears came to Fenway to play a team of Army All-Stars in a pre-season game, for the benefit of helping the war effort in 1942.  A couple of years later the National Football League returned to Boston in the form of the Boston Yanks and called Fenway their home.  The Yanks would share the field as their home in 1948 with Boston University, although it would be the last year for the Yanks, because they would move to New York in 1949, ultimately moving to Baltimore as the Colts. 

B.U. continued to play home games at Fenway for the next few years.  An interesting note in Fenway history happened on November 12, 1949.  On that day Vin Scully, the iconic Dodgers broadcaster, made his professional debut when he provided the play-by-play for CBS Radio from the roof of the first base grandstand, when B.U. played Maryland.

In 1949, the legendary Harry Agganis appeared at Fenway for the first time, piloting the Boston University Terrier football team. In 1951, the future Red Sox first baseman left B.U., joined the Marines and appeared at Fenway Park as a member of the baseball team from Camp Lejeune, North Carolina.  He batted cleanup for them in the game, and helped lead the camp's team over Boston College's baseball team. In the fall, Agganis returned to play football once again for Boston University and on October 13, 1951, led B.U. to a 16-0 victory over his former teammates on the Camp Lejeune football squad. 

In the fall of 1953, Boston University left forever and moved to play all their football games at Braves Field, now Nickerson Field.  Boston College's football team then returned to Fenway, for the first time since 1945, and continued to play there until 1956 when the decision was made to end Fenway being used for football games. 

In 1963 Patriots' owner Billy Sullivan partnered with Tom Yawkey to push the city to build a new stadium.  In the meantime, Yawkey allowed his new ally to use Fenway Park as his home field. The duo pushed the city to build a taxpayer financed new 60,000 seat domed stadium, with a retractable roof in the South Station section of Boston.  But the city, as before, had no desire to fund a private stadium and the plan didnít see the light of day. The Pats would eventually leave Fenway in 1968, marking the end of Fenway Park's football era.