Doing a tour of Oceania and being prepared to be corrected by any with superior google fu:
I believe New Zealand, like Canada and Australia has had Prime Ministers with military service but of rank below captain.
Fiji has been lead by many generals and the current PM is Rear Admiral Bainimarama.
Solomon Islands and Western Samoa I believe have only had civilian PMs.
Since independence Papua New Guinea has not had a flag ranked military PM.
Indonesia has mostly been ruled by generals including Sukarno, Suharto and Yudhoyono
Malaysia has had only civilian PMs since independence.
Singapore’s 3rd Prime Minister was Lee Hsien Loong who was Brigadier-General.
An interesting case is East Timor. Xanana Gusmão was a corporal in the Portuguese army then lead the independence militia but he’s never been a general. OP’s call but I’d vote to exclude Timor-Leste.
Khruschev was not regular Army, he was a Communist Party political Commissar (both Russian Civil War and WWII). He had been a professional politician for almost all the interwar period. His wartime rank was determined solely by political status rather than military experience.
Well, see there’s many variables in Austria. Certainly the King/Emperor held high military rank.
Then which office is leader? Chancellor? President? President is largely ceremonial. But Seyss-Inquart was the last pre-war Chancellor and he achieved the rank of SS Gruppenführer, which is indeed a “General” level rank, but that rank was more or less honorary.