Mr. Hack joined Apollo in 2023 in Enterprise Solutions as the Chief Operating Officer of Engineering. Prior to that time, he was a Managing Director and Chief Operating Officer of Electronic Trading Engineering at Citadel from 2020 to 2023. From 2008 to 2020, John held multiple global technology and operational leadership roles at D. E. Shaw and its spin-off Arcesium. He spent his early career in consulting and software development for AIG, Random Walk Computing, and Accenture.

Mr. Hack graduated from Duke University with a BSE degree in Electrical and Computer Engineering with a second major in Computer Science.