Federer, who was already the most successful player in the history of the tournament, was competing in his 15th final in his hometown after seeing off No. 3 seed Stefanos Tsitsipas in a straight-sets semifinal win on Saturday.
Meanwhile, 20-year-old De Minaur was vying for his fourth career title, with the previous three having all come this year in Atlanta, Zhuhai and his hometown of Sydney.
Top seed Federer struck early, breaking his Australian opponent’s serve at 2-1 before doing so again at 5-2 to take the first frame with his second set point.
The 38-year-old carried his momentum into the second set, breaking De Minaur’s serve at the first opportunity before holding for a 3-0 lead.
The deficit proved too much for De Minaur to reduce, and the set followed serve as Federer finished the week with a straightforward 6-2, 6-2 victory.
The win was Federer’s fourth in a final this year, with the 20-time Grand Slam champion having already collected titles in Halle, Miami and Dubai this season.