On 12 July 2014, Guardiola signed for CD Eldense after scoring nine goals in the 2013–14 campaign while playing for Novelda CF. On 14 May of the following year, he agreed to a three-year deal with AD Alcorcón, which was made effective on 1 July. Guardiola made his professional debut on 22 August 2015, coming on as a second-half substitute for Óscar Plano in a 2–0 Segunda División home win against Córdoba CF. On 24 December, after being rarely used, he terminated his contract.
On 28 December 2015, Guardiola signed a one-and-a-half year deal with FC Barcelona, being assigned to its reserves in the third tier. However, just hours later, he was released after the discovery of offensive tweets about the club and Catalonia made in 2013. He claimed they were made by a friend as a joke, and that he had not noticed they had been posted.
Granada
On 8 January 2016, Guardiola joined another reserve side from the same league, Granada CF B, for the remainder of the campaign. He made his debut later that day, putting his team ahead with a penalty kick in a 1–1 draw at CD San Roque de Lepe. Guardiola was promoted to Granada CF's first team by new manager Paco Jémez in July 2016, appearing regularly during the pre-season and also being an unused substitute in the opening game of the new season against Villarreal CF. However, after the arrival of new signings, he was deemed surplus to requirements and was loaned to A-League club Adelaide United FC on 13 September 2016. On 27 January 2017, Guardiola moved to Real Murcia also in a temporary deal.
Córdoba
On 2 July 2017, Guardiola signed a two-year contract with second division side Córdoba after cutting ties with Granada. On 20 December, he scored a hat-trick in a 5–0 home routing of CF Reus Deportiu. On 13 March 2018, Guardiola agreed to a four-year extension at the Andalusians, raising his release clause to €15 million. On 22 June, after netting 22 goals and narrowly avoiding relegation, he signed a one-year loan deal with Getafe CF in La Liga. Guardiola made his debut in the Spanish top flight on 31 August 2018, replacing Ángel late into the 0–0 home draw to Real Valladolid.
Valladolid
On 25 January 2019, Valladolid reached an agreement with Córdoba for the transfer of Guardiola, who signed a contract until 2023.
