Among the best-known examples are Kinoshita's calculations of the anomalous magnetic moments of the electron and the muon.

While at the Institute for Advanced Study he calculated to high precision the ground state energy of Helium.

[6] In 1962 he showed that Feynman amplitudes in quantum electrodynamics remain finite in the limit of propagator masses vanishing, i.e., all infrared divergences cancel.

In the 1970s he worked on quantum chromodynamics and quarkonium - spectroscopy with Estia Eichten, Kenneth Lane, Kurt Gottfried, and Tung-Mow Yan.

The sixth-order term consists of 72 Feynman diagrams, and Kinoshita evaluated these to high precision numerically using computers.

[15] In 2001, Kinoshita and a group in Marseille found a sign difference in their respective calculations of the π0 pole contribution to the sixth-order light-by-light amplitude.

[16] Kinoshita and his student M. Hayakawa ultimately traced this to an incorrect implementation of the antisymmetric Levi-Civita tensor εαβγδ used in the computation code "Form"[17] that had been used.

[21] He was survived by daughters and sons-in-law Kay and Alan Schwartz, June and Tod Machover, and Ray and Charles C. Mann, three sisters in Japan, and six grandchildren.

He was awarded the Sakurai Prize from the American Physical Society in 1990; the SUN-AMCO Medal from the International Union of Pure and Applied Science in 1998; the Gian Carlo Wick Gold Medal in 2010; and the Toray Science and Technology Prize in 2019.