Born in Valencia, Valencian Community, Gil was a product of Valencia CF's youth system, having joined the club at the age of five. He made his senior debut at only 17 with the reserves by playing one game in Segunda División B, being brought to the main squad for the 2010, 2011 and 2012 pre-seasons and scoring the third goal in the latter against SV Rödinghausen ; shortly after, he earned a professional contract until 2016. Gil was loaned to neighbouring Elche CF for the 2012–13 campaign. He first played in Segunda División on 19 August 2012, starting in a home game against SD Ponferradina and netting in an eventual 4–2 win; he scored in the following match, a 2–1 victory at Hércules CF. After being a very important attacking unit as the club returned to La Liga after nearly 25 years, Gil remained with Elche for 2013–14, still owned by the Che. He made his debut in the competition on 19 August 2013, in a 0–3 loss at Rayo Vallecano. Gil scored his first goal in the top flight on 1 March 2014, the game's only goal in a home win over RC Celta de Vigo. He subsequently returned to Valencia, making his league debut on 29 August in a 3–0 home defeat of Málaga CF. Gil netted his first league goal for Valencia on 28 September 2014, contributing to a 1–1 away draw against Real Sociedad.
Gil joined Premier League side Aston Villa on 13 January 2015 for a fee in the region of £3.2 million, signing a four-and-a-half year deal and receiving the number 25 jersey. He made his debut four days later, as a 59th-minute substitute for Ashley Westwood in a 0–2 home defeat to Liverpool. Despite the result, manager Paul Lambert described his performance as "as good a debut as I've seen". Gil made his first start on 25 January 2015 in an FA Cup tie against Bournemouth, scoring from the edge of the box to open a 2–1 victory. Thirteen days later he contributed his first assist for the Villans, allowing Jores Okore to score through a close-range header in a 1–2 home defeat to Chelsea. Gil netted for the first time in the league on 13 September 2015, putting his team 2–0 up in an eventual 2–3 loss at Leicester City. The following 2 January, away to Sunderland, he equalised with an aerial volley from compatriot Adama's cross, but in a 1–3 defeat against their relegation rivals.
Deportivo
On 20 July 2016, Gil returned to his homeland's top flight, being loaned to Deportivo de La Coruña with an option to buy. The following 12 July the move was extended for a further season, with an obligatory buyout clause included; his team was eventually relegated, and he played only six minutes after the appointment of new coach Clarence Seedorf.
