The new club played its first match on 15 August 1903, a 1–1 draw with Stenhousemuir - the goalscorer was William McAulay. That first season produced a win in the Aberdeenshire Cup, but only a third-place finish in the Northern League. Undaunted, the club applied for membership of the Scottish League for the following season, and were duly elected, although to the Second Division, rather than the First which the directors had aspired to.
With the arrival of League football in 1904–05, Aberdeen changed kit colours to black and gold, resulting in the new nickname of the Wasps. The club at this time was managed by Jimmy Philip, and he steered the club to a Scottish Qualifying Cup win on 26 November 1904, a 2–0 victory over Renton at Dens Park. At the end of that first season, despite having finished seventh out of 12 teams, Aberdeen were elected to the new, expanded First Division, and have been in the top tier of Scottish football ever since, a record shared with only Celtic.
Once in the First Division, however, the club's progress was steady rather than spectacular – a Scottish Cup semi-final appearance in 1908 and another in 1911 being the highlights of the pre-war period. In that season of 1910–11, Aberdeen recorded their first victories over the Old Firm, and led the league for a time, but the silverware ended up in Glasgow, as was becoming customary.
Wartime affected the club as much as any other, and in spite of spending cuts and other economies, by 1917 the situation was untenable and, along with Dundee and Raith Rovers, Aberdeen dropped out of competitive football.