An open cockpit anachronism by the time World War II began in September 1939, th C.R. did not even enter service with the Regia Aeronatica until two months later in November. Even when initial design work on the Falco began in 1936 as a development of the C.R.41, world-wide aeronautical design was leaving the biplane behind for the all-metal monoplane. Nevertheless, a marked remained for the elegant aircraft with examples eventually being sold to Belgium, Finland, Hungary and Sweden. Pilots, even the knew they were outclassed, enjoyed flying the C.R.42, as long as they could stick to close air support and stay away from enemy fighters. Most Italian Falcos were stationed in North Africa and the Mediterranean, but a detach of 50 were flown from Belgium during Battle of Britain from October 1940 to January 1941. They where slaughtered by British fighters. Production of the Falco was finally stopped in early 1942 and the type was withdrawn from front lines as quickly as possible. From that point on most Falcos flew in lead - in fighter transition groups and this is probably where the aircraft was most appreciated due to it's sparkling handling characteristics.

The CR.42 was exported to Belgium, Sweden and Hungary, seeing combat in both Belgium and Hungary. Regia Aeronautica used them on all fronts (e.g. North Africa, Mediterranean, Battle of Britain and East Africa). The Luftwaffe used 150, as night attack aircraft in relatively quiet theatres.