The initial production of 41 aircraft was delivered to civilian customers and the Portuguese Navy. Production then switched filling orders for both the Navy and Coast Guard for a light amphibian utility transport designated as J4F-1. The Coast Guard acquired 25 J4F-1 aircraft purchased in two groups. The initial order consisted of eight aircraft delivered from Grumman on 7 July 1941. These aircraft were given USCG service numbers V197 through V204. The following year the second batch, consisting of 17 aircraft, was acquired. The first J4F from this batch was delivered to the Coast Guard on 25 February 1942 and the final was delivered on 29 June 1942. These aircraft were given the service numbers V205 through V221.
In addition to utilizing the J4F-1 as a utility transport the Coast Guard intended to use them for search and rescue purposes. The Coast Guard J4F-1, basically the civilian G-44 Widgeon, differed only in the addition of a hatch on top of the fuselage, just behind the wing, for loading stretchers. With the advent of World War II these aircraft were assigned to coastal anti-submarine patrols and a wing rack was added to each aircraft beneath the starboard wing. These racks could hold a depth charge, a bomb, a raft, or search and rescue gear. A J4F-1 patrolling out of the Houma, Louisiana, piloted by Chief Aviation Pilot Henry C. White, was credited with sinking the U-166 on 1 August 1942 in the Gulf of Mexico. In the year 2001 this was determined to be in error when a diving operation located the U-166 in a position different from the location of White’s attack. White’s aircraft has been preserved in the Naval Aviation Museum in Pensacola, FL.