Luis Enrique
The former Barcelona player repeated the feat achieved by his one-time teammate, Pep Guardiola, by winning the treble in his first year in charge, the 2014-15 season. He followed it up with a double in his next season.
Interestingly, though, Enrique had a rocky start to his managerial career at Barcelona. He changed his line-ups continuously in the first few matches and that unsettled the squad. This policy also reportedly led to a quarrel with Lionel Messi and several other influential team members. However, the Spaniard soon settled in with his first 11 and things began to fall in place and Barcelona went on to climb greater heights.
Unfortunately, the pressure of the high-profile job eventually got to him and the 49-year-old left Nou Camp after three years even though he was offered a new deal. Valverde has been in charge since then.