Crowell announced on Twitter, of course, that he "made the decision to leave Twitter" adding that, "It's been a joy to work here and to build an extraordinary team of immensely talented people across the globe."
He joined Twitter in September 2011 in the same role he's leaving.
In a series of tweets on Thursday, Crowell praised friends and colleagues at Twitter and didn't provide details on whether he has another job lined up.
"I'm looking forward to winding down at Twitter over the next few months and then kicking back, relaxing a bit, and enjoying time with my family," he wrote.
Crowell also said he will continue to be "a passionate supporter of the power of open conversation and the people who use Twitter. I feel lucky to have been part of it."