With the commencement of the 1973 season, the leagues twentieth anniversary, the Northern Football Conference had become the only remaining senior football league in Canada. The remaining senior teams in the Province of Ontario, the Bramalea Satellites and the London Lords applied for admission to the northern league and were welcomed but the London team never participated in the league. With the addition of the southern team and no other senior leagues in Ontario the Northern Football Conference became a province wide league and its champions were recognized as Ontario Provincial Champions.
Despite the growth in the first twenty years the league experienced rough times following its anniversary. With the folding of the Laurentian University team after the 1973 season and the Bramalea Satellites withdrawing to compete at the Ontario junior level after the 1974 season the Northern Football Conference had declined to three teams for the 1975 season, Sudbury Spartans, North Bay Ti-Cats and Sault Ste. Marie Steelers. Interest in competing at the senior level appeared to be waning in Ontario. The league decided to attempt innovations to encourage new clubs to join the league. The innovations included adopting a summer schedule for the 1976 season and playing with four downs rather than the traditional three downs. The summer schedule was accepted because it is more suited to weather conditions in northern communities and it would allow University players an opportunity to further hone their skills during their summer holidays by competing in the Northern Football Conference. The change to four downs was accepted because of the adoption of this rule by many of the high school leagues in Ontario.
The innovations proved a boon as the Orillia Silver Bombers joined the league commencing in 1976 making the league a solid four-team league. With some newfound stability, many applications for league expansion began to appear.
The league championship had new meaning during this five-year period as it was also recognized as the Ontario Provincial championship. The Bramalea Satellites captured back to back crowns in their only two years in the league (1973-1974) and the Sault Ste. Marie Steelers returned to league prominence by capturing back to back championships (1975-1976) as well. Sudbury added its eleventh title to its illustrious list of accomplishments when the Spartans captured the championship in 1977.