Llenas joined Fox News in September 2010 as a correspondent for Fox News Latino. Llenas assumed the added position of a correspondent for Fox News Channel in July 2013 and became a full-time New York based correspondent in July 2016. 
Most recently, Llenas became the first non-French journalist to fly with the precision aerobatic demonstration team of the French Air Force, Patrouille de France. In 2016, he provided on-site coverage of the Latino vote from both the 2016 Republican National Convention and the Democratic National Convention. Llenas also extensively reported onsite from the terror bombings in Manhattan and New Jersey in September 2016. 
During his tenure at Fox News Channel and Fox News Latino, Llenas has covered a wide array of stories, including the January 2015 North American blizzard, the 2014 World Cup live from Brazil and the assassinations of NYPD officers Rafael Ramos and Wen-Jen Lu. He has also reported on the inauguration of Pope Francis live from Rome, the Pope’s subsequent visit to the U.S., Hurricane Sandy, Super Bowl XLVIII as well as the 2012 Republican National Convention and Democratic National Convention. 
In addition, Llenas has interviewed governors, senators, celebrities and athletes. 
Llenas is considered to be one of the Top 50 Latino voices to follow on Twitter. As a member of the inaugural launch team that developed FOX News Latino, he has covered key issues including immigration, politics and news affecting the Hispanic community.