Rubuta ci gaba ga wannan sakin layi - Ba da daɗewa ba bayan barkewar Yaƙin Duniya na Biyu a watan Satumbar 1939, Laftanar Janar Sir Thomas Blamey ya nada Vasey a cikin ma'aikatan sashen na 6. A watan Maris na 1941, Vasey ya dauki umurnin Brigade na 19 na Infantry, wanda ya jagoranci a yakin Girka da yakin Crete. Da ya koma Australia a 1942, an ba Vasey girma zuwa babban janar kuma ya zama Mataimakin Shugaban Babban Jami'in. A watan Satumbar 1942, ya dauki umurnin 7th Division, ya yi yaƙi da Jafananci a cikin yakin Kokoda Track
da kuma yakin Buna-Gona. A cikin 1943, ya shiga yaƙin neman zaɓe na biyu a New Guinea, yana jagorantar Rukunin 7th a Landing a Nadzab da kuma kamfen ɗin Finisterre Range na gaba.