The Allegheny team was assembled in 1890. At that time athletic clubs and associations, ranging from the best with extensive facilities to local organizations with minimum meeting rooms, were in their prime as a source of fraternal fellowship for athletes. In most sports, Allegheny provided very little competition for the more established East End Gymnasium Club (EEGC), which in 1892 became the Pittsburgh Athletic Club. Allegheny soon took up football largely when the club discovered that it could give them a recruiting edge over the East Enders. Many Allegheny club members had gone to eastern colleges and played football. Members O. D. Thompson and John Moorehead, were former teammates of Walter Camp, the inventor of the modern game, who had become a successful Pittsburgh lawyer. The team also immediately gave Allegheny a strong following since the East Enders did not have a football team at the time. Allegheny's backfield during that inaugural year had A. S. Valentine, at quarterback; two track stars in Harry Oliver and Harry Fry as the halfbacks; and O.D. Thompson at fullback.
In what may have been the first official football game in modern-day Pittsburgh, the club's inaugural season began on October 11, 1890, when Allegheny played the Western University of Pennsylvania (later renamed the University of Pittsburgh) at Exposition Park, on what is today the parking area between PNC Park and Heinz Field, in front of a crowd of 500 spectators. Allegheny won the game easily, 38-0, but the contest was significant since it marked the official start of Pitt's football program. Prior to the game, Allegheny was to play Shady Side Academy, however the team failed to show up for the game and were replaced by the Western University team. Allegheny went on to defeat Shady Side Academy a week later, 32–0.
Although the eleven players styled themselves the "All-Pittsburghs", they were really a collection of local athletes masquerading as a team. Significantly, several of the pick-ups were members of the East End Gym such as William Kirschner and Grant Dibert. This game foreshadowed the start of the upcoming rivalry between Allegheny and the Pittsburgh Athletic Club. Allegheny would go on to defeat the inexperienced team by a score of 22–6.
November 1, 1890 Allegheny scheduled a game against the Princeton University Preparatory team, paying them $150. The prep team was a far cry from the Princeton's varsity team. Allegheny would end up losing to the touring Princeton team, 44–6. The season concluded with a 6–6 tie with the Detroit Athletic Club and a 6–4 loss to the Cleveland Athletic Club, both amateur club squads. However, the Allegheny Athletic Association was regarded as the local champions that season.