Early in his career, Paley was a Consultant and the Monitor Group. In 1999, he became the Co-Founder and CEO of Abstract Edge an online marketing digital agency that focused on technology organizations. From 2002-2008, Paley was the Co-Founder, CEO, and General Manager for Brontes Technologies; the company would later be acquired by 3M.
Paley was the Entrepreneur-in-Residence at Harvard Business School from 2011-2015. In January 2009 alongside David Frankel and Micah Rosenbloom, Paley became Co-Founder and Managing Partner at Founder Collective. The majority of the funds Founder Collective invested in companies came from the co-founders' own personal wealth. During his tenure at Founder Collective he led the fund's investment in Uber, as well as FormLabs, Hotel Tonight, MakerBot, and Integral Ad Science.
Paley wrote The TradeDesk's first term sheet in 2010 and is still a board member at the company. He was also a seed investor in autonomous vehicle pioneer Cruise Automation, which sold to General Motors in 2016 for more than $1 billion. Paley is on the Board of several companies including Integral Ad Science, Contently, The Trade Desk and more. In 2018, Paley was included on The Midas List of Top Tech Investors of 2018 in Forbes.