 Pari gbolohun ti o tẹle: Underhill ni olori ẹgbẹ ikọkọ ikọkọ lakoko ikọkọ ni Kwajalein Atoll. O de pẹlu 25th Marine Regiment ati ki o ṣe ifọkanbalẹ awọn ilẹ-ilẹ pẹlu atilẹyin artillery. Samuel C. Cumming gba ipò Underhill gẹgẹ bí olùrànlọwọ olórí ẹka ní 11 April 1944. O ti ni igbega si ipo ti olori-ogun ni May 1944 ati tun ṣe ọṣọ pẹlu Legion of Merit fun awọn igbiyanju rẹ lakoko Ogun Agbaye. : Iṣẹ Kwajalein. 