John Gage was based on the real firefighter turned paramedic Jim Page, who helped create the firefighter/paramedic program for LAFD. Executive Producer Jack Webb wanted to name the character after Page, but he declined. Jim Page died on 4 September 2004 and Randolph Mantooth was one of the speakers at his memorial.
Fire Station 51 is in real life Los Angeles County Fire Station 127 located at 2049 E. 223rd Street in Carson. Furthermore, although the actual station crew has never included a paramedic unit, Harbor UCLA Medical Center, the actual hospital that is portrayed as Rampart, is the closest hospital to it so it would be the regular medical facility Station 127 would deal with. The station is still in service with little change. The second Engine 51 used in the show is now in service at the Yosemite National Park in California. You can find the engine at the small fire station near the visitors center.
'Emergency!' was truly a family affair because Julie London was at the time married to co-star Bobby Troup and had been hired by her previous husband Jack Webb who was the series' creator and producer.
During the show's run, it was credited with actually saving lives. There were many news reports over the years of children and adults saving people using techniques demonstrated in the series. However in later seasons, the series posted a disclaimer in the credits noting that the medical techniques demonstrated should only be performed by people with proper formal training in them.
The Harbor UCLA Medical Center served as Rampart Emergency Hospital in the series. The hospital is located in Torrance, California. 1000 West Carson Street. This is appropriate, as this hospital (then known as Harbor General) served as the initial training facility for the Los Angeles County Paramedic Training Program.
On CHiPs (1977), the fictitious Engine and Squad 51 respond to a motor vehicle accident, in the episode titled "MAIT Game"; moreover, it isn't just two pieces of apparatus with the same number - it is the Ward-LaFrance Engine and Dodge Utility body, even shown pulling out of the 51 Stationhouse. However, the crew is not shown because "Emergency!" had already gone off the air.
The radio call sign KMG365, which is said whenever Station 51 is responding to a call, is still a valid FCC call sign licensed to the LACoFD. It appears on the station patches for the crew at Station 127, which was used as the filming location for Station 51.
During his recurring role on Emergency! (1972), the character Officer Vince played by Vince Howard, rotated from being a member of the Los Angeles Police Department and the Los Angeles Sheriffs Department.
Paramedics Gage and Desoto sometimes crossed paths with Reed and Malloy from Adam-12 (1968), another Jack Webb show, at Rampart Hospital. In Emergency!: Hang-Up (1972), the firefighters are watching Adam-12: Ambush (1971) when they're dispatched to a call. Throughout the rest of the show, the firemen are on the phone to anyone, trying to find out what they missed.
The series originated when producer Robert A. Cinader was in the Los Angeles area researching for a new medical drama series. There, he learned of the fledgling paramedic program being tested in the Los Angeles County Fire Department. Upon learning the full details of the program and the nature of their dispatches, Cinader immediately concluded the adventures of such a team of special firefighters would be excellent material for a TV series.