An electronic device may include an electronic circuit, a heat sink thermally coupled to the electronic circuit, and spaced apart cooling fins extending from the heat sink. Each cooling fin includes a circuit board and a cooling device mounted thereon. The cooling device may have a conductive trace layer on the circuit board defining an electromagnet, a mounting member extending upwardly from the circuit board, a fan blade coupled to an upper end of the mounting member to be movable in a rocking motion about an axis defined by the mounting member, and a permanent magnet carried by the fan blade and responsive to the electromagnet.