As a doctor, Ito developed a vaccination against smallpox. He also widely studied the Japanese flora and fauna with Philipp Franz von Siebold, the author of Fauna Japonica and Flora Japonica. Rhododendron keiskei was named after him.
He wrote a translation of Flora Japonica titled Taisei honzou meiso (Japanese:"泰西本草名疏") that was published in 1829.
Ito became a professor at the University of Tokyo in 1881.
He died in 1901, and he was ennobled with the title of baron (danshaku).
A statue of Ito keisuke
His translation of Flora Japonica