Born in Lloret de Mar, Girona, Catalonia, when Muniesa was only 15 years old there were already transfer rumours that Chelsea wanted to sign him. At the La Masia youth academy he developed quickly, and was ready to appear for FC Barcelona's first team at the age of 17. Muniesa made his debut for Barça's first team aged 17 years and 57 days on 23 May 2009, as a substitute in a 1–0 La Liga home loss against Osasuna for the already crowned league champions. This appearance made him the second youngest player ever to feature for Barcelona, but he only played a few minutes, being sent off after a challenge on Antonio Hidalgo; the following Wednesday, he was named amongst the substitutes for the 2009 Champions League Final against Manchester United.