Sporting Clube de Portugal has already celebrated, adhering to historical accuracy, one hundred years of history and is still counting. Some suggest that the Club is indeed older, using the founding dates of other institutions and ignoring long periods of inactivity during periods of ephemeral existence as criteria for the setting of a foundation date. Others suggest that Sporting Clube de Portugal's date of foundation be relative to the founding date of Sport Club de Belas (1902) or the Campo Grande Sporting Club (1904). However the date of foundation of Sporting Clube de Portugal is fixed, within the Club's statutes, as the 1st of July 1906.
 
The routes of the footballing tradition of Sporting can clearly be traced back to the founding period of 1906. However, this was also an eclectic period for the multiple variations of athletics practiced by the founders of the Club. The founding members of the Club where devoted athletes, as well as practitioners of the disciplines of football, tennis, tug-of-war, fencing, cricket, gymnastics and field hockey.
 
In 1907, D. Fernando de Castelo Branco (Pombeiro) authorised the use of the lion from his coat of arms, but without its blue background. "Not with a golden gun of red on a blue field, as was Pombeiro's, but with a silver gun of black on a green field, that clearly affirms the intentions of the founders", notes Júlio de Araújo, speaking about the creation of the Sporting symbol. The green exterior was in fact suggested by the Viscount of Alvalade, symbolising hope for the new Club.
 
The 3rd of February 1907 played witness to Sporting's first game of football. It cannot be said, however, that the club met with immediate success: losing 5-1, in the second division, in a greatly disputed game in Alcântara. However, some of the players from the winning side would later join sporting: Alípio da Motta Veiga, Octávio Teixeira Bastos, António das Neves Vital and others. D. João de Vila Franca scored the only goal for Sporting in the game: A goal that would be the first in the history of Sporting.
 
On the 1st of December 1907, an eternal rivalry was born. Sporting Clube de Portugal and Sport Lisboa (that would only become known as Sport Lisboa e Benfica in the following year) played their first football match, on the pitch at Quinta Nova, in Sete Rios. Sporting, who dressed in white during its first few years, began the game wearing a shirt divided vertically into green and white for the first time (today known as the ‘Stromp’ kit), with white shorts. Sporting won that game 2-1 (goals from Cândido Rosa Rodrigues and Cosme Damião), in the first game between the nation's two greatest rivals.

The Club had, what was considered at this level, the best pitch in Portugal in the form of the Moorish site. Located then at 73 Alameda do Lumiar, today known as Alameda das Linhas de Torres, the pitch was located in terrain made available by the Viscount of Alvalade from his farm. The pitch was in use as early as May 1906 and was improved later in 1907. The pitch and surrounding sports complex housed a football pitch, athletics track, 2 tennis courts and a pavilion with showers, baths and a kitchen. A pavilion that was, at the time, a luxury.

1910 would also be an important year for Sporting, as its Tennis teams claimed titles in pole vaulting, shot put and long jump. This was also the year that José Alvalade would assume the presidency of the Club: An office he would hold until 1916.