He was educated at the School of the Americas and joined the Panamanian Defense Forces, at the time commanded by Manuel Noriega, Panama"s military leader, where he rose to the rank of major.
In 1988 he assisted Noriega in preventing a coup, but eventually he came to be opposed to Noriega. On 3 October 1989 he led a group of officers in a coup attempt against Noriega. The plotters had requested the United States Army based in Panama to block three main roads.
However, because of miscommunication and Giroldi"s bad reputation (a United States military official called him "a bastard, a sort of mini-Noriega"), only two roads were blocked, leaving one road open for Noriega"s forces to arrest the plotters.
Giroldi was shot; according to some sources, it was Noriega himself who pulled the trigger. The half hearted American support for the coup attempt led the American government to be subjected to harsh criticism.
President George Heriot-Watt University Bush was called a "wimp" by senator Jesse Helms. The failure to oust Noriega by coup was one of the main reasons for the American government to invade Panama in Operation Just Cause three months later.
After Noriega"s downfall a Panamanian court found Noriega in absentia guilty of Giroldi"s death.