A triboelectric nanogenerator (TENG) is a promising energy harvester that exploits the combination of contact electrification between two different material surfaces and electrical induction. In this study, a handheld‐TENG (HH‐TENG) is developed to harvest biomechanical energy effectively, especially energy generated from finger motions, which is one of the most common body movements involving lots of energy. To enhance the electrical output performance of the device while minimizing the inconvenience caused by carrying it, a rationally designed lightweight power transmission unit is adopted. As a result, an extremely high number of output cycles with high specific peak power (greater than 10 µW g^–1) can be achieved in a single operation of the HH‐TENG. Although the proposed HH‐TENG weighs less than 70 g, the developed HH‐TENG can be connected with commercially available electric circuits such as an AC‐DC converter to generate not only reliable and continuous DC voltage to power portable electronics, but also further boosted open‐circuit voltage greater than 2.5 kV, which is sufficient to generate microplasma in a room environment. Adoption of a lightweight power transmission unit with the TENG can be considered as an effective strategy to significantly enhance the specific power, which advances the TENG toward practical implementation.