The Stirling-based medal hope will be targeting gold in Tuesday’s final after finishing nearly half a second quicker than his nearest rival at the Tokyo Aquatics Centre on Monday in a time of 1:44:60.
Scott, 24, won two silvers in Rio in 2016 and the multiple world and European champion is keen to add to his medal haul after winning gold in the Commonwealth Games three years ago.
His Team GB colleague Tom Dean also reached the final after finishing fourth.
Speaking to the BBC after the semi-final, Glasgow-born Scott said: “Quite a few [swimmers] went slow in the first semi-final so I knew we had a good opportunity.
"We took that so we've got a good chance tomorrow.”
Asked about the hopes of both him and Dean medalling tomorrow Scott was optimistic, replying: “It would be really exciting, we're in a great position going into tomorrow morning."
Monday proved fruitful for Britain's swimmers after Adam Peaty picked up gold in the men’s 100m breaststroke, making history in the process as the first British swimmer to successfully defend an Olympic title as he finished the 100m breaststroke in a time of 57.37 seconds – six-tenths clear of his rivals.
Scott’s compatriot Kathleen Dawson finished third in her 100m backstroke semi-final, reaching the final as the fifth-fastest, but there was disappointment for Cassie Wild who could only manage 14th place while Sarah Vasey just missed out on a place in the women’s 100m breaststroke final.