Legia Warsaw's origins lie not in the capital but on the First World War front. The football team was formed in March 1916 near Kostiuchnówka in Volhynia, among soldiers of Józef Piłsudski's Polish Legions. After the Legions were dissolved in the autumn of 1917, the club suspended its activity for several years before being revived in Warsaw in 1920 as a Military Sports Club. The name Legia was restored following a merger with the capital's oldest club, Korona, in 1922.
The club's current colours, red, white, green and black, and its crest featuring the letter "L" in a black circle, were formally adopted at a general meeting on 2 July 1957, when, after years operating as CWKS Warsaw (1950-1957), the historic name was also restored. In 1936 Legia suffered the only relegation from the top flight in its history. The club returned to the elite after the war, in 1948, and has never left it since.
Legia won its first Polish championship relatively late, only in 1955, but from then on steadily built its dominant position in Polish football. The club has won 15 Polish titles (some club-published counts list 16, including the disputed 1992/93 title later stripped after controversy surrounding the so-called "Sunday of Miracles"), along with a record 21 Polish Cups and 5 Polish Super Cups, making Legia the most decorated club in the history of Polish football.
On the European stage, Legia went furthest in the 1969/70 season, reaching the semi-finals of the European Cup, where they were eliminated by eventual champions Feyenoord. A year later they reached the quarter-finals of the same competition. In 1990/91 the club reached the semi-finals of the Cup Winners' Cup, and in 1995/96, as the first Polish side to reach the Champions League group stage, advanced all the way to the quarter-finals. The club's more recent history has also produced memorable clashes with European heavyweights, including eye-catching encounters with Real Madrid and Borussia Dortmund in the 2016/17 Champions League, while in 2024/25 Legia reached the quarter-finals of the UEFA Conference League.
Legia play their home matches at the Polish Army Stadium on Łazienkowska Street, whose "Żyleta" stand is famous across Europe for its fanatical support and spectacular, often controversial tifo displays. Legia's status makes it the most emotionally charged club in Poland, adored by millions of supporters and resented by rivals in equal measure, with every victory in classic encounters against Lech Poznań or Wisła Kraków further cementing its position as the sporting and organisational giant of Polish football.