1970's - Johan Cruyff
There is no doubt in the fact that Johan Cruyff, the manager has been more influential to Barcelona than Johan Cruyff, the player. But that doesn't change the massive impact he made during his five-year-long playing career at the Catalonian side.
As discussed, Barcelona had failed to win La Liga since 1960. Already a three-time European champion with Ajax, Barcelona signed him in 1973 for a world record fee. By winning the La Liga 1973-74 season, the talismanic forward ended the club's 14-year long league drought in his very first year.
Although he won only one league and cup with the club, the psychological impact he made was massive. During his short-spell, he helped the fans, players and the club itself regain their spirit and confidence. So much that even Real Madrid, a club that dominated them for so long, was beaten 5-0 by Cruyff-lead Barcelona. They could now boast of a world-beater who also happened to be the first three-time Ballon d'Or winner.