Football's premier club competition was launched one month after UEFA's first Congress, held in Vienna on 2 March 1955 yet, curiously, the so-called "European Cup" was not a UEFA initiative.

Whereas many of UEFA's founder members were more interested in establishing a national team competition, the French sports daily L'Equipe and their then-editor Gabriel Hanot, were championing the cause for a European-wide club competition. Hanot, together with colleague Jacques Ferran, designed a blueprint for a challenge tournament to be played on Wednesdays under floodlights.

The tournament initiated by L'Equipe did not stipulate that the participating teams had to be champions of their country, but they invited clubs who they considered had the most fan appeal. Representatives of 16 clubs were invited to meetings on 2 and 3 April 1955 and the L'Equipe rules were unanimously approved. The first European Champions Clubs' Cup fixture was played in Lisbon and Sporting Clube de Portugal were held to a 3-3 draw by FK Partizan. The Yugoslavian side won the return leg in Belgrade 5-2 to advance to the next round.

Real Madrid CF immediately made the tournament their own by winning the first five finals. Since then, other clubs have also enjoyed fruitful runs in the competition with AFC Ajax and FC Bayern München both completing three consecutive wins. However, no one club has been able to claim long-term domination. Ajax waited 22 years to add a fourth title to the hat-trick obtained in the early 1970s; Madrid's win in 1998 was their first in 32 years; and Bayern's penalty shoot-out success in Milan in 2001 ended a 26-year wait for their fourth success.

Liverpool FC's four victories between 1977 and 1984 deserve special mention as the English club won its four trophies with essentially different teams. The Reds' European pedigree shone brightly again in 2005 when they battled back from 3-0 down to defeat AC Milan on penalties in what was perhaps the competition’s most exciting and memorable final.

Real Madrid, Milan and FC Barcelona have been the most successful sides in the UEFA Champions League, winning the competition three times. Madrid are also the most successful side overall with nine triumphs, followed by seven for Milan, five for Liverpool and four each for Bayern, Ajax and after their 2011 triumph, Barcelona. Madrid also hold the record for final appearances, with 12. Milan's 2002/03 success came after a marathon 19 games from the third qualifying round of the competition all the way to their penalty shoot-out success against Juventus in the final.

The major turning point in the evolution of the competition came in the 1992/93 season when the UEFA Champions League, involving a group stage in addition to the traditional knockout elements, was officially inaugurated after a pilot round robin during the previous season. The popularity of the group phase means the competition has grown from eight to 32 teams with matches taking place on Tuesdays and Wednesdays across Europe.