Gregory akabva asvika kuMarine Corps Base San Diego muna June 1927 uye akashanda semukuru mukuru wepositi kusvikira muna December 1928, paakaenda kuNicaragua kunoshanda kechipiri. Akabatanidzwa kuChipiri Marine Brigade pasi paBrigadier General Logan Feland uye akashanda semubatsiri kune brigade quartermaster kusvikira aendeswa semukuru we "Guardia Nacional de Nicaragua". Ari munzvimbo iyi, akabatsira mubasa rokuyamura maererano nokudengenyeka kwenyika muManagua muna March 1931
uye akarumbidzwa nomunyori weNavy neRed cross. Akagamuchira Nicaraguan Presidential Order of Merit neGoridhe nyeredzi uyewo Medal of Merit nesirivha nyeredzi nokuda kwebasa rake muNicaragua.