He was an early Bitcoin user and received the first bitcoin transaction from Bitcoin's creator Satoshi Nakamoto. Finney lived in the same town for 10 years that Dorian Satoshi Nakamoto lived, adding to speculation that he may have been Bitcoin's creator. Finney denied that he was Satoshi Nakamoto.

In March 2013, Finney posted on a Bitcoin forum BitcoinTalk that he was essentially paralyzed, but continued to program. He continued to program until his death; he was working on experimental software called bcflick, which uses Trusted Computing to strengthen Bitcoin wallets.

During the last year of his life, the Finneys received anonymous calls demanding an extortion fee of 1,000 bitcoin. They became victims of swatting — a hoax "where the perpetrator calls up emergency dispatch using a spoofed telephone number and pretends to have committed a heinous crime in the hopes of provoking an armed police response to the victim’s home"