Llompart reached his highest individual ranking on the ATP Tour on December 23, 2013, when he became World number 725.

He reached his highest doubles ranking on July 21, 2014, when he became World number 232.

Llompart partnered with countryman José Perdomo in the men's doubles competition at the 2010 Central American and Caribbean Games, winning the bronze medal.

He also partnered with countrywoman Monica Puig in the mixed doubles competition at the 2010 Central American and Caribbean Games, winning the bronze medal.

Llompart also represented Puerto Rico at the 2011 Pan American Games, reaching the second round in the men's singles competition and falling in the first round in the mixed doubles competition.