He launched The Twenty Minute VC podcast with $50 and not a single contact in VC. The first episode was released on 10 January 2015 and was an interview with Guy Kawasaki. Harry left his job at venture capital firm Atomico in May 2017 after six months since he began working there. In 2018, he co-founded Stride.VC with Fred Destin with £100,000,000 but later stepped down as partner.
Forbes 30 Under 30 in Europe list included Harry in the finance category in 2019. In May 2020, he launched his venture capital fund, 20VC fund and raised a further US$140,000,000 in funding in June 2021. Currently, the fund focuses on investments in the United States with an average investment size of US$500,000.