On February 15, 1903, a group of young men sitting in the former "U Českého dvora" Hotel in Kladno decided to establish their own sports club, at which they "cultivated" the new game of the time – football. On that day, the chapters of the rich history of Kladno football began to be written.
The first team played under the name of the Kladno Sports Club (Sportovní klub Kladno) in 1905. It soon achieved a strong position among the Czech rural teams and also achieved good results in matches with the high quality Prague clubs. The first championship encounter took place in Kladno as early as 1908 when AFK Kolín was defeated to the tune of 5–1.
The Kladno team played continually in the highest football competition between 1925 and 1947 before being expelled from the league in the 1946/47 season for the manipulation of results. The club later returned to the top flight several times, specifically in 1948–49, 1952–58 and 1960–65. The club's last premier league season for almost four decades was in 1969–70. The waiting for promotion to the top flight was until 2006.
In the statistics for the highest Czechoslovak club competition (1925–1993) SK Kladno ranks 8th among the Czech clubs. The club played a total of 618 matches, acquired 558 points and had a goal difference of 1189–1398 in the highest league competition.
Ever since 1907 when Slovan Wien left Kladno with a 1–8 defeat, Kladno has maintained international sports relations. As early as 1908, the well-known English team Crystal Palace F.C. played in Kladno and over the years SK Kladno has encountered teams from 34 countries in four continents (Europe, Asia, Africa and America). The most frequent international opponents have been European teams, in particular those from Norway, France, Germany and Austria. Throughout the period of its existence, SK Kladno has also participated in a number of significant football tournaments. These have included the popular Central European Cup (1934, 1938, 1961), the Rappan Cup 1964 and the city competition in Belgium (Brussels 1931 and Liege 1932 and 1938). In 1934, the Kladno team undertook its longest ever international trip to the USA, which proved to be good promotion not only for Czechoslovakia, but also European football.
A number of important footballers began their football in the blue and white of Kladno or wore it at some time during their careers. Among them were Otakar Škvain-Mazal (1894–1941), a pupil of SK Kladno and the author of three goals at the Antwerp Olympics in 1920 where the Czechoslovak national team made it to the final. František Kloz (1905–1945), Kladno's most popular player and most active goal scorer (592 goals in Kladno colours) and a Czechoslovak international player who, like his teammate, Josef Kusala, laid down his life with a gun in his hand during the liberation of his homeland in 1945. Karel Kolský (1914–1984), a player and coach of Czechoslovak national team. Jan Fábera (1928–1984), a player SK Kladno, who successfully trained the national team of Sudan and was active as a coach in Algeria and Iceland. From 1971–72, he and Jozef Vengloš trained the Czechoslovak under-23 team, which won the European Championship. Josef Kadraba (born 1933), a Kladno striker and a player and coach for Slovan Wien, but mostly a member of the Czechoslovak national team, which surprised many by achieving the silver medal at the 1962 FIFA World Cup in Chile. Jan Suchopárek (born 1969), a Kladno pupil, a player with 61 caps in the national team. In 1996, he brought back "silver" for the second place at the Euro held in England. It should also be recalled that the legendary Czech striker and long-time player at Slavia Praha, Josef Bican (1913–2001), trained the Kladno first team in the 1962–63 season.