Prior to joining the Fire Department, Ganci served in the
82nd Airborne Division. Having never been deployed, Ganci was on leave at home with a firefighter friend who told him about the death of four firefighters from Engine 18 in the
23rd Street Fire in Manhattan. Ganci, at that moment, realized that there is a dangerous aspect to fighting fires as well. While still a volunteer with the Farmingdale Fire Department, Ganci was with the same friend one day who told him he was planning to transfer to another station in the city. Following the conversation and his discharge from the Army in 1968, Ganci signed up and was accepted into the New York City Fire Department in 1968. Ganci joined the New York City Fire Department in 1968, serving in engine and ladder companies in Brooklyn and the Bronx, beginning with Engine Company 92 in the Bronx and then subsequently Ladder Company 111. During this time in the FDNY, a time described by
The New York Times as "an era of crisis", fire companies battled arson fires almost continually in the city's poorest neighborhoods. Ganci was promoted to lieutenant in 1977, captain in 1983, battalion chief in 1987, and deputy chief in 1993, when he was working in
Bedford-Stuyvesant, Brooklyn. In 1994 Ganci was made the head of the Bureau of Fire Investigation following the appointment as fire commissioner of
Howard Safir, who needed a uniformed chief to address conflicts between fire marshals and uniformed firefighters, a conflict whose resolution Safir credits to Ganci. In January 1997 Ganci replaced his boss
Donald Burns as Chief of Operations, the second highest uniformed position in the Fire Department.
During the September 11 attacks ’s South Pool, along with those of other first responders. On the morning of the attacks, Ganci's best friend and executive assistant, Steve Mosiello, was going to drive Ganci to court, where Ganci had been scheduled for jury duty. However, immediately after
American Airlines Flight 11 hit the North Tower (
1 World Trade Center) at 8:46 a.m. Ganci, Mosiello, and Chief of Operations
Danny Nigro rushed there from their command post in
downtown Brooklyn. Driving there in Ganci's car, they arrived on the scene in less than 10 minutes, and set up a command post on a ramp leading to a garage near the North Tower, in time to see
United Airlines Flight 175 hit the South Tower at 9:03 a.m. Ganci's fire team, including Mosiello, pulled it from beneath four feet of debris.), and their daughter Danielle, who lived with Ganci in
Massapequa, New York. ==Legacy and memorials==