Kasvi held a Ph.D. in Engineering from the Helsinki University of Technology.

Kasvi was previously the editor in chief of Kosmoskynä, the magazine of Finnish Science Fiction Writer's Association, a games reviewer in the computer magazine MikroBitti, and a columnist in the computer games magazine Pelit under the pseudonym Wexteen the Wizard.

An avid fan of Star Trek, he added a Klingon version to his campaign re-election website in 2007.

He was also a member of the city council of Espoo from 1997, and the second vice-president of the International Parliamentarians' Association for Information Technology (IPAIT) from 2004.

In January 2021, Kasvi wrote in his blog that the cancer had spread to his liver, his treatments had been stopped, and that he had been moved to end-of-life care.