Takamine was born at Takaoka in Japan, the son of a physician. Although brought up along traditional lines, he nevertheless received a modern scientific education at the Tokyo College of Science and Engineering, where he graduated in chemical engineering in 1879. After two years' training at Anderson's College, Glasgow, he returned to Japan in 1883 and entered the government department of agriculture and commerce. In 1887 he left to establish the first factory for the manufacture of superphosphates in Japan.

In 1890, having married an American, he settled permanently in America. He set up a private laboratory and in 1894 produced Takadiastase, a starch-digesting enzyme, which had applications in medicine and the brewing industry.

It had been demonstrated in 1896 that an injection of an extract from the center of the suprarenal (adrenal) gland causes blood pressure to rise rapidly. In 1901 Takamine managed to isolate and purify the substance involved – adrenaline (epinephrine). This was the first isolation and purification of a hormone from a natural source.