Scott Morrison prevailed in battleground states where voters feared his opponent’s policies would threaten jobs.

Australian conservative Prime Minister Scott Morrison’s surprise come-from-behind win in national elections was fueled by a campaign that focused on fears that economic and climate policies pledged by center-left opponents would end the world’s longest growth streak. Mr. Morrison, who once carried a lump of coal into Parliament to illustrate the importance of commodity exports to the resource-rich economy, sealed victory in battleground states where many voters worried his Labor rivals would drive up living costs and threaten mining jobs with their environmental plans. “I have always believed in miracles,” Mr. Morrison, an evangelical Christian, said in a speech to jubilant supporters gathered at a Sydney hotel after Saturday’s election. He credited his victory to “quiet Australians”—whose voices were largely not reflected in voter polls that for more than two years showed his Liberal-National coalition facing election defeat. Throughout his campaign, the 51-year-old Mr. Morrison focused on a simple argument: Conservatives are better managers of the economy.

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