By early 1918, when the first production examples of the Nieuport 28 became available, the SPAD S.XIII was already firmly established as the standard French fighter, and the Nieuport 28 was "surplus" from the French point of view. On the other hand, the United States Army Air Service was desperately short of fighters to equip its projected "pursuit" (fighter) squadrons. Since the SPAD S.XIII was initially unavailable due to engine shortages, the Nieuport was offered to the American Expeditionary Force (AEF) as an interim alternative.
A total of 297 Nieuport 28s were purchased by the Americans, with the 94th and 95th Aero Squadron receiving the initial allotments, starting in March 1918. In all, four AEF pursuit squadrons: the 27th, 94th, 95th and 147th Aero Squadrons, flew Nieuport 28s operationally for various periods between March and August 1918.
The factory delivered the Nieuport 28s to the Americans in mid-February 1918 without armament. At the time the AEF had no spare Vickers machine guns to supply to the squadrons, so that the first flights were unarmed training flights for pilots to familiarize themselves with the handling and performance of the new type. When deliveries of Vickers guns to the American squadrons finally started in mid-March, and until sufficient guns had been received for all of the fighters to be fully equipped, some aircraft were flown on patrol with only one machine gun fitted.
On 14 April 1918, the second armed patrol of an AEF fighter unit resulted in two victories when Lieutenants Alan Winslow and Douglas Campbell (the first American-trained ace) of the 94th Aero Squadron each downed an enemy aircraft over their own airfield at Gengoult. Several well-known World War I American fighter pilots, including the 26-victory ace, Captain Eddie Rickenbacker, began their operational careers on the Nieuport 28. Quentin Roosevelt (the son of U.S. president Theodore Roosevelt) was shot down and killed flying the type.
The 94th and 95th had the task of dealing with the type's teething troubles. Initially undercarriages failed on landing - this was corrected by using heavier bracing wire. The Nieuport 28's 160 hp Gnome Monosoupape rotary engine and fuel system proved unreliable and prone to fires. Field improvements to fuel lines, and increased familiarity of the American pilots (and their ground crews) with the requirements of monosoupape engines reduced these problems, but the definitive solution adopted was simply not completely filling the reserve fuel tank, at the expense of range. More seriously, a structural problem emerged – during a sharp pull out from a steep dive, the plywood leading edge of the top wing could break away, taking the fabric with it. On the whole, although the pilots of the 94th and the 95th appreciated the manoeverability and good handling of the Nieuport, and were reasonably happy with its general performance but some regarded the type as fragile and dangerous.
The 27th and 147th Aero Squadrons arrived at the front three months later, starting combat operations on 2 June 1918. In July 1918, the 94th and 95th Aero Squadrons received their first SPAD XIIIs and some of their surviving Nieuport 28s were then transferred to the 27th and 147th Aero Squadrons. By the end of August 1918, all four American squadrons were fully outfitted with SPAD XIIIs. The pilots of the 94th and 95th Aero Squadrons welcomed the SPADs, although the 27th and 147th Aero Squadrons were much less enthusiastic about the change.
Twelve of the Army Nieuports were transferred to the U.S. Navy which equipped them with Royal Navy style hydrovanes and wing floatation gear, and flew them from launching platforms mounted above the forward turrets of eight battleships, in the same way that Sopwith Camel 2F.1s were used by the British Grand Fleet.
Postwar, approximately 50 new Nieuport 28As which had not previously seen service were shipped to the U.S. During the 1920s, Nieuport 28s were also in service with various air forces; Switzerland obtained 15, while Argentina received a couple of aircraft. Switzerland acquired its examples in 1919, and continued to fly the type throughout the 1920s, retiring their last Nieuport 28s from active service in 1930.
During the same period, a number of Nieuport 28s made their way to Hollywood where they appeared in the movies, The Dawn Patrol (1930), as well as its remake in 1938, Ace of Aces (1933) and Men with Wings (1938). The Nieuport 28s appeared in several later films set during WWI, including the Lafayette Escadrille (1958).