Charlie Miller, a former National Security Agency hacker who is the one of the world's best-known security experts, declined to comment on his departure or say what he would do next.
A Twitter spokesman could not immediately be reached for comment.
Miller's latest feat, breaking into a moving Jeep as it drove on the highway, was done with IOActive researcher Chris Valasek and was the subject of talks at this month's security conferences in Las Vegas.
Their efforts, which were coordinated with manufacturer Fiat Chrysler Automobiles NV , prompted the first vehicle recall to protect drivers from possible malicious hacking.
FCA USA LLC recalled 1.4 million vehicles to install software intended to prevent hackers from emulating the experiment, which used the cellular network to enter the entertainment system and then win control of the engine, brakes and steering.
Shares in Twitter, which is seeking a permanent chief executive officer, have fallen by more than 40 percent from the first day of trading in 2013 level and set a record low as the broader market sank on Monday.
© Thomson Reuters 2015
For the latest tech news and reviews, follow Gadgets 360 on X, Facebook, WhatsApp, Threads and Google News. For the latest videos on gadgets and tech, subscribe to our YouTube channel. If you want to know everything about top influencers, follow our in-house Who'sThat360 on Instagram and YouTube.