In the fall of 1914, when the war front moved away from Paris, the American Ambulance set up an outpost in Juilly and sent out detached units of volunteer drivers to serve informally with the British and Belgian armies in the north.

The newly appointed inspector toured the ambulance sections of Northern France and learned that the American volunteers were bored with so-called "jitney work," transporting wounded soldiers from railheads to hospitals far back from the front lines.

[6] In March 1915, Andrew met with Captain Aimé Doumenc, head of the French Army Automobile Service and pleaded his case for the American volunteers.

[11] There, it grew rapidly over the next year, continuing to provide "sanitary sections" to the French Army, while also serving as a recruitment source of combat pilots for the newly formed Escadrille Lafayette,[12] one of whose prime movers, Edmund L. Gros,[13] was the Field Service's in-house physician.

Before the AFS was absorbed into the much larger, federalized U.S. Army Ambulance Service,[15] it had numbered more than 2500 volunteers, including some 800 drivers of French military transport trucks.

At the same time, a large percentage of volunteers signed up for the military, thenceforth members of USAAS units, but remaining identified with their AFS past—a past kept alive through the work of HQ, still at 21 rue Raynouard, where a Bulletin[19] was published and where visiting ambulance drivers could find temporary lodgings and meals.

[26][27] The AFS recruits who joined the Service in late spring 1917, after Congress's declaration of war, were greeted by Piatt Andrew with a request: Would they forego ambulance driving for trucking supplies to the front?

[28] After the war the Field Service produced three hefty volumes of writings from numerous AFS alumni, including excerpts from the previously published books above.

[29] Following the Great War, the AFS became sponsors for the French Fellowships[30]—graduate student scholarships for study in France and in the US—which were ultimately administered by the Institute of International Education and were precedents for the Fulbright Foundation exchanges.

AFS also created an association for its veterans, publishing a bulletin,[31] organizing reunions and contributing a wing to house its memorabilia at the Museum of Franco-American Cooperation in Blérancourt, France.

During the 1947–48 school year, the first students came from ten countries including Czechoslovakia, Estonia, France, Great Britain, Greece, Hungary, the Netherlands, New Zealand, Norway and Syria.

On a European level, the European Federation for Intercultural Learning (EFIL) serves as the umbrella organization for many AFS partner countries in and around Europe, currently including 26 AFS partner countries: Austria, Belgium (both Flemish and French organizations), Bosnia and Herzegovina, Czech Republic, Denmark & Sweden, Egypt, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Netherlands, Norway, Poland, Portugal, Russia, Serbia, Slovakia, Spain, Switzerland, Tunisia, Turkey and Tunisia.

The main activities include networking and advocacy, training and seminars for volunteers and staff, establishing new partner countries in Europe, and coordinating Europe-wide projects.

[37] AFS is an international, voluntary, non-governmental, non-profit organization that provides intercultural learning opportunities to help people develop the knowledge, skills and understanding needed to create a more just and peaceful world.

NSLI-Y encourages a lifetime of language study and cultural understanding by providing more than 600 fully funded scholarships to American high school students.

As of 2023, NSLI-Y offers academic scholarships to learn Arabic, Mandarin Chinese, Hindi, Indonesian, Korean, Persian (Tajiki), Russian, and Turkish through summer and year-long programs in Jordan, Morocco, China, Taiwan, India, Indonesia, South Korea, Tajikistan, Estonia, Latvia, Kazakhstan, Kyrgyzstan, Turkey, and other countries around the world.

As of 2023, students come to the US from a variety of countries in Eurasia including Armenia, Azerbaijan, Czechia, Estonia, Georgia, Greece, Hungary, Kazakhstan, Kyrgyzstan Latvia, Lithuania, Moldova, Mongolia, Montenegro, Poland, Romania, Serbia, Slovakia, Tajikistan, Turkmenistan, Ukraine, and Uzbekistan.

As of 2023, students come from the following countries: Albania, Bahrain, Bangladesh, Bosnia & Herzegovina, Bulgaria, Cameroon, Egypt, Gaza, Ghana, India, Indonesia, Israel, Jordan, Kenya, Kosovo, Kuwait, Lebanon, Liberia, Libya, Malaysia, Mali, Morocco, Mozambique, Nigeria, North Macedonia, Pakistan, Philippines, Saudi Arabia, Senegal, Sierra Leone, South Africa, Suriname, Tanzania, Thailand, Tunisia, Turkiye, and the West Bank.

[49] The YES Abroad Program also provides scholarships for high school students in the US to spend an academic year in countries with significant Muslim communities, including as of 2023 Bosnia & Herzegovina, Bulgaria, Ghana, India, Indonesia, Jordan, Malaysia, Morocco, North Macedonia, Senegal, Thailand, and Turkiye.