Haller, like all Swiss schoolchildren at the time who wished to enter a trade or profession, enrolled in an apprenticeship when he was 16 years old, and trained at the famed Park Hotel in the ski resort town of Davos, Switzerland. After graduating from high school at the age of 18, he served in the Swiss Army, and although World War II was raging he never saw combat. Discharged at the age of 20, he spent several years working at the exclusive Hotel Des Balances in Lucerne, where he attended the Hotel Training School—considered one of the best cooking academies in the world. He then moved to the five-star Hotel Belle-Vue-Palace in Bern, and then the Grand Hotel in Bürgenstock. While working there as chef tournant (filling in as needed on stations in the kitchen), the hotel owner asked if he would move to Canada to cook at another company-owned property, and Haller readily agreed.