American Legion was a steel-hulled, twin-screw passenger and cargo steamship, laid down as yard hull number 242 on 10 January 1919 under a United States Shipping Board (USSB) contract at Camden, New Jersey, by the New York Shipbuilding Corporation.

[15] By 1924 Aeolus and Huron had dropped off the New York-Rio de Janeiro-Montevideo-Buenos Aires route to be replaced by sister "535's" Pan America and Western World.

Over the next few months, the ship made five round-trip voyages to the Canal Zone, with stops at Charleston, South Carolina, and San Juan, Puerto Rico, carrying civilian and military passengers.

There, she was to embark the Crown Princess Märtha of Norway and her party and bring them to the United States, their homeland having fallen to the Germans the previous spring.

"[4] American Legion — her neutrality shown clearly by the U.S. flags painted prominently on her sides — sailed for Finland on 25 July, and reached Petsamo on 6 August, as scheduled.

The Army troopship also embarked a host of American nationals and refugees from a variety of countries: Poland, Finland, Estonia, Latvia, Lithuania, Sweden, Norway, Denmark, Germany, and the Netherlands, the total number of people being 897.

Before she sailed on the 16th, after an almost Herculean effort involving taking this special cargo by truck the entire length of Sweden, the transport loaded a twin-mount 40-millimeter Bofors antiaircraft gun, "equipped with standard sight, and accompanied by spare parts and 3,000 rounds of ammunition."

The transport unloaded the Bofors brought from Petsamo, whence it was shipped to Dahlgren, Virginia, where it would be tested, and ultimately adopted by the US Navy and produced domestically.

[4] American Legion soon returned to the more prosaic calling she had pursued since earlier in the year, that of an Army transport, and resumed the regularly scheduled service between New York and the Panama Canal Zone.

Ultimately, as the United States expanded her defense perimeter, American Legion supported this movement, transporting men and cargo to such ports as Hamilton, Bermuda, and Port-of-Spain, Trinidad, as well as to Cristóbal, in the Canal Zone.

[4] American Legion — whose cargo included Army Air Corps gear earmarked for use by the 33rd Pursuit Squadron (whose Curtiss P-40 fighters were flown off from Wasp) — reached Reykjavík, Iceland, on 6 August.

On the afternoon of 22 September, as she neared her destination, her local escort — two Army planes — arrived overhead and accompanied the ship on the last leg of her voyage.

[4] American Legion reached San Juan three days later, mooring at Pier 7, Puerto Rico Dock Company, shortly after noon.

Ultimately, though, it was the small seaplane tender USS Thrush that came to the rescue, passing a line to the crippled transport at 16:50 and taking her in tow back to San Juan.

Ultimately, on 23 October, American Legion reached Pier 2, Army Base, Brooklyn, and disembarked her passengers — civilian workers and naval dependents evacuated from Puerto Rico.

[4] Assigned to the Naval Transportation Service (NTS) on 6 February American Legion embarked men slated for duty at a destroyer base being established at Derry, Northern Ireland, and sailed, in convoy, on the first leg of her voyage, bound for Halifax.

[4] On 9 April 1942, American Legion sailed from New York for the Panama Canal Zone, bound, ultimately, for Tongatapu, in the Tonga, or Friendly Islands, which she reached on 8 May 1942.

There she disembarked her passengers — Army officers, nurses, and enlisted men who were to establish a field hospital on Tongatapu — and proceeded on to Wellington, New Zealand, arriving there on 29 May.

American Legion remained at Wellington through mid-July, earmarked for participation in the United States' first offensive landing operation in the Pacific War — the invasion of Guadalcanal, in the Solomons.

During that training and practice evolution, the ship embarked war correspondent Richard Tregaskis, whose experiences would later be chronicled in the book, Guadalcanal Diary.

[4] That afternoon, while the landings proceeded apace, American Legion joined in the antiaircraft barrage that repelled the initial Japanese air attacks on the invasion fleet, as she did the next day.

Discharging cargo at "Red" Beach on the morning of 8 August, the transport got underway as a wave of Japanese twin-engined bombers came after the shipping off Guadalcanal.

At noon, American Legion sighted the incoming planes, which dropped their bombs near the supporting cruisers and destroyers before heading toward the amphibious ships.

[4] During the action, one Mitsubishi G4M1 Type 97 land attack plane ("Betty") passed from starboard to port directly over American Legion's stern, at 100 feet (30 m).

Transport Group "X-ray" ceased discharging cargo and darkened ship, remaining shut down for the rest of the night, crews at general quarters.

Within a half-hour, American Legion got underway, the majority of her cargo having been unloaded by her busy boat crews who had labored almost continuously since the 7th with almost no sleep and subsisting only on sandwiches and coffee.

[4] Over the next several months, American Legion carried out a series of supply runs, including as ports of call Guadalcanal;Tulagi; Auckland, New Zealand; Nouméa; Brisbane, Australia; and Espiritu Santo, in the New Hebrides.

[4] Troop and cargo runs then followed, between Auckland, New Zealand; Nouméa, New Caledonia; and Guadalcanal, before she put into Efate, in the New Hebrides, on 22 October 1943, in preparation for the invasion of Bougainville, Solomon Islands.

[4] Arriving off Cape Torokina, Bougainville, on the morning of 1 November 1943, American Legion proceeded into the earmarked transport area in Empress Augusta Bay and anchored at 06:46.

Based at the Amphibious Training Case at Coronado, California, American Legion operated in the training capacity for the duration of World War II, exercising off Coronado, off Aliso Canyon, near Oceanside, California, and the Marine Corps Base, Camp Pendleton, and at Pyramid Cove, near San Clemente Island.