Born in L’Hospitalet de Llobregat, Barcelona, Catalonia, Alba started his career in the youth ranks of Barcelona as a left winger, but was released by the club in 2005 for being too small. He then joined neighbouring club Cornellà and, after almost two years, departed in a €6,000 transfer to Valencia where he finished his football education.

After returning to Los Che, Alba made his La Liga debut on 13 September 2009, in a 4–2 win at Real Valladolid. He then started in two consecutive UEFA Europa League group stage matches, against Lille and Slavia Prague (both 1–1 draws, respectively away and home). Due to continuing injuries in Valencia’s defence, he played much of 2009–10 as a left back, posting overall good performances. In that position, on 11 April 2010, he scored his first goal for the club, in a 2–3 away loss to Mallorca.

Alba received his first call-up to the full side on 30 September 2011, for the last two UEFA Euro 2012 qualifiers against the Czech Republic and Scotland. He made his debut in the latter game on 11 October, a 3–1 win in Alicante in which his cut back from the left wing provided the assist for the opening goal, scored by former Valencia teammate David Silva. His impressive debut confirmed his status as a strong candidate to be the long-term successor of Joan Capdevila as the regular left back for La Roja, and he was also included in the under-23 squad for the 2012 Summer Olympics in London.

On 22 June 2012, Alba signed a five-year contract with Barcelona for a transfer fee of €14 million. He made his official debut on 19 August, playing the full 90 minutes in a 5–1 home win against Real Sociedad.

Alba scored his first goal for the Blaugrana on 20 October 2012, the opener in a 5–4 win at Deportivo de La Coruña, and scoring an own goal. In the following game, at home against Celtic in the Champions League group stage, he found the net in the 93rd minute of a 2–1 win.

On 12 March 2013, Alba scored his fifth goal of the campaign, scoring in the last minute to complete Barcelona’s 4–0 home win over A.C. Milan in the Champions League round of 16 after a 0–2 loss, when his team was the first in the competition’s history to overturn such a deficit. He ended his first year at the Camp Nou as league champion, as Tito Vilanova’s side regained the title from Real Madrid.

On 2 June 2015, Alba agreed to a new five-year contract with a new buyout clause of €150 million. Four days later, he started in the Champions League final, helping the club to its fifth win in the competition by beating Juventus at Berlin’s Olympiastadion. He made 38 appearances in all competitions, with one goal,) as Barça won a treble.

On 22 May 2016, Alba won the second Copa del Rey of his career, scoring in the 97th minute of the final against Sevilla after a through pass from Lionel Messi, in an eventual 2–0 extra time win at the Vicente Calderón Stadium.

On 11 March 2019, Alba agreed to a new five-year contract with a new buyout clause of €500 million.