He started his career with Barcelona, first appearing with the first team at the age of 17, and was loaned to Everton and Sevilla before joining the former on a permanent deal in the summer of 2015.

Deulofeu was also a Spanish youth international, having represented the country over 80 times at under-16, under-17, under-19, under-20 and under-21 levels, being named the UEFA Under-19 Championship Golden Player in 2012.

[citation needed] On 29 October, he made his professional debut with the main squad, replacing Cesc Fàbregas in the 63rd minute of a 5–0 league home success against Mallorca.

[17] He helped his team to record its best ever Premier League points tally of 72 to finish fifth[18] and, at the end of the campaign, Barcelona confirmed that he would not be returning for a second loan spell as he had been promoted to their first-team squad;[citation needed] he wrote an open letter thanking the staff, players and fans for their support during his stay.

[20] However, on 14 August 2014, Sevilla reached an agreement with Barcelona for the loan of Deulofeu for the coming season,[21] with the player admitting "surprise" at Enrique's decision.

[22] After being an unused substitute in a 1–1 home draw against Valencia, Deulofeu made his debut on 30 August replacing Vitolo in the 73rd minute of a 2–1 away win against Espanyol.

[24] On 24 September Deulofeu scored his first goal for the Andalusians (and also his first ever in the top flight in Spain), netting the game's winner in a home success over Real Sociedad.

[27] He scored his first goal as a permanent Everton player, a free kick at the Madejski Stadium, as they came from behind to win 2–1 against Reading in the third round of the League Cup.

[30] Two days later, he made his debut with Milan in a Coppa Italia quarter-final match against Juventus, coming on as a substitute for Carlos Bacca in the 1–2 defeat.

[53] A quick and skillful player, gifted with pace, good technique and dribbling ability, Deulofeu is capable of playing as a winger or as a forward on either flank.

[61] Despite citing Ronaldinho as his main inspiration,[62] Deulofeu's style of play is comparable to that of Cristiano Ronaldo, due to a shared direct approach.

[65] Looking back in 2018, NBC Sports' Daniel Karell said of Deulofeu: "In his younger days, the now 24-year-old winger was a dynamic and lightning-quick attacker with a central midfielder's technique to boot".