Garrick is best known for his research on monetary and distributed systems innovation, particularly cryptocurrencies and blockchain technology. 

Garrick's blockchain research is some of the most cited and downloaded, and he was ranked as one of the 100 most influential economists in the UK & Ireland. He is a regularly invited speaker to various private and public sector institutions, including the CIA, US Army and Naval War Colleges, Federal Reserve, Bank of England, Bank of International Settlements, and the Financial Stability Board. Garrick is also frequently asked to share his research and perspective with the media, including the BBC, CNBC, FT, WSJ, and NPR.

Notable cryptocurrency and blockchain research publications include the first "Global Cryptocurrency Benchmarking Study" (University of Cambridge) and "Global Blockchain Benchmarking Study" (University of Cambridge). He also created and published the CoinDesk "State of Bitcoin" and "State of Blockchain" reports from 2013-2016. Garrick's other research interests include sovereign debt, financial crises, financial repression and prudential regulation, black markets, and systemic risk. He completed his PhD in economic history at the London School of Economics under the supervision of professors Albrecht Ritschl and Niall Ferguson.

Garrick's teaching includes developing the UK's first university taught class on blockchain technology at the University of Cambridge and teaching on numerous executive education programs and classes for Cambridge, Oxford, Columbia, Northwestern, Imperial College of London, and the London School of Economics, where he was a visiting fellow from 2020-22.