Early years and Castellón Born in
General Roca, Río Negro, Ulloa started his career in 2002, playing with
Primera B Nacional side
Comisión de Actividades Infantiles. In 2005 he moved to the
Primera División, signing for
San Lorenzo where he was part of the squad that won the
2007 Clausura. Shortly after, Ulloa joined
Arsenal de Sarandí. In the summer of 2008, after a brief stint with
Olimpo, He scored 16 goals in his
debut season, his team's best and sixth in the league.
Almería Ulloa posted similar numbers in
2009–10, but Castellón were relegated after finishing 22nd and last. In late June 2010 he moved to another club in the country,
Almería, signing a five-year contract. On 13 September 2010, in only his second official match for the
Andalusians, Ulloa scored in the
last minute for a 2–2
La Liga home draw against
Real Sociedad, after an individual effort. The following month, against the same opponent in the
Copa del Rey's
round-of-32 first leg, he netted twice in the last 20 minutes to help his team come back from 2–0 to win 3–2 in the
Basque Country. On 22 December 2010, again in the domestic cup, Ulloa scored three goals and
assisted on another, as Almería beat
Mallorca 4–3 in the first leg, winning 8–6 on aggregate. On 16 January 2011 he took his league tally to five, netting in a 1–1 home draw against
Real Madrid after finishing a move from countryman
Pablo Piatti. Ulloa was crowned the
2011–12 season's top scorer at 28 goals, but Almería failed to regain their top-flight status after finishing seventh.
Brighton & Hove Albion in 2013 On 16 January 2013, Ulloa transferred to
Championship side
Brighton & Hove Albion on a four-and-a-half-year deal, for an undisclosed fee believed to be around £2 million. He scored on his debut ten days later, in a 2–3 home loss against
Arsenal in the
fourth round of the
FA Cup. On 2 March 2013, Ulloa became the first ever player to score a
hat-trick at
Falmer Stadium, during Brighton's 4–1 win over
Huddersfield Town. Two weeks later, he scored twice against
Crystal Palace in a 3–0 victory also at home, contributing to his team's first home win in the
M23 derby since 1988; manager
Gus Poyet described him as "different class", and he continued his scoring run on the 30th, with his ninth goal in 12 matches coming in a 2–2 draw at
Nottingham Forest. On 27 April 2013, Ulloa scored the goal that confirmed
Brighton's place in the Championship play-offs, heading the 88th-minute winner to secure a 2–1 away defeat of
Leeds United.
The following season, on 3 May 2014 and again through a
header, he netted in the last minute to once again send them to the play-offs, helping to a comeback at Nottingham Forest and 2–1 win.
Leicester City in 2014 On 22 July 2014, Ulloa joined
Leicester City on a four-year contract for a club record £8 million, being handed the number 23 shirt. He started on his
Premier League debut at home to
Everton on 16 August, and scored after 22 minutes as his team twice came from a goal down to secure a 2–2 draw. He found the net in his third appearance, against Arsenal on 31 August for another home draw (1–1), and scored the only goal of the match to help defeat
Stoke City for the side's first win of
the campaign. On 21 September 2014, Ulloa contributed a brace in a 5–3 home win over
Manchester United. After nine games without a goal, he scored but in a 2–1 loss at
Aston Villa. During January 2015, Ulloa scored in
FA Cup victories over
Newcastle United and Tottenham, helping the Foxes to reach the fifth round. On 18 April, he netted his first league goal of 2015 in a 2–0 win against
Swansea City which saw Leicester move off the bottom of the table for the first time since November 2014. Two weeks later, he scored twice in the 3–0 victory over Newcastle for his team's fifth win from six matches. Under
Claudio Ranieri, Ulloa played mostly second-fiddle to
Shinji Okazaki and
Jamie Vardy in
2015–16, but still managed 29 games and six goals as Leicester won the first top-flight league title of their 132-year history, including one in the last minute of a 1–0 defeat of
Norwich City at the
King Power Stadium on 27 February 2016 which caused celebrations that led to a small earthquake registering on the
Richter scale. Ulloa struggled to break into the first team following the signings of
Ahmed Musa and
Islam Slimani in
2016–17, prompting an enquiry from Swansea City. He did not start his first league match of the season until 2 January 2017, in a goalless draw against
Middlesbrough, and late into that month he submitted a transfer request, which led to bids from
Alavés and
Sunderland; these were rejected, as well as a subsequent loan offer from
Galatasaray, leading the player to express in a
Twitter post that he felt "betrayed by Ranieri" and vowed not to play for Leicester again. A total of three bids from Sunderland, ranging from £3 million to £7.5 million, were rejected as Leicester were unwilling to sell him to a relegation rival. On 24 August 2017, aged 31, Ulloa signed a new contract at Leicester, extending his link until June 2019. He struggled to break into the first team during
the season, only totalling 19 minutes in the league in four substitute appearances; thus, on 29 January 2018, he completed a loan move to Brighton & Hove Albion for his second spell. Ulloa scored his first goal for Brighton since 2014 on 17 February 2018, in a home 3–1 home win against
Coventry City in
the FA Cup. His first in the league came on 9 May, but in a 3–1 loss away to
Manchester City; shortly after, having appeared in 12 competitive matches, he revealed he was hoping to earn a permanent move.
Pachuca On 10 August 2018, Ulloa joined
Liga MX club
Pachuca. His first goal for his new team, a header, opened the scoring in a 2–0 win over
Celaya in the
Copa MX.
Rayo Vallecano On 30 August 2019, Pachuca announced Ulloa's departure to
Rayo Vallecano via
Twitter. ==International career==