Jimmy was born in Miami, Florida. The son of Venezuelan immigrants from Barquisimeto, he spent summers with his parents in Venezuela. He later commissioned into the United States Marine Corps. In 2006, Jimmy was deployed to Afghanistan where he became commanding officer of First Lieutenant Jack Ryan. He later sent Jack and twelve other marines to the village of Korengal to extract a family that had been marked as collaborators by the Taliban. Unfortunately, a grenade was detonated aboard their helicopter by a boy named Sahim, whom Jack had allowed to come with them, resulting in the helicopter crashing. Jimmy was the first to arrive at the crash site and found Ryan as the sole survivor. After stabilizing him, Jimmy escorted Jack to Bagram Air Base and joined him on a C-130 transport to Landstuhl Regional Medical Center in Germany. After receiving three surgeries to his spine, Jack awoke a month later. Jimmy was the first person Jack saw after awakening and visited him every day while he was in the hospital for the next three months.
Jimmy later separated from the military where he met and married his wife Vanessa and had three kids. He then ran a successful campaign to be elected as a U.S. Senator and served on the Senate Intelligence Committee. In late 2018, Jimmy convinced Jack Ryan to leave his job as the CIA Head of T-FAD to become his legislative fellow on Capitol Hill.
Jimmy goes to meet Jack at a CIA lecture about global threats, especially those concerning Venezuela. Afterwards he takes Jack back to a birthday party hosted by the Moreno family. Moreno then works with Ryan to follow up an arms shipment recently sent to Venezuela.
They go on a diplomatic mission to meet with Venezuelan President Nicolas Reyes in Caracas. Jimmy takes Jack and James Greer to dinner. Greer has arrived from Moscow following the same ship that also held their arms shipment. However the day after they arrive the convoy is ambushed and attacked by a sniper, Max Schenkel. As they try and flee their burning car Schenkel fatally shoots Moreno. The loss is devastating to Ryan, who after losing his best friend in front of his eyes, can barely speak.