Kroll worked as an engineering manager at Right Media, a subsidiary of Yahoo!, from 2007 to 2009 and as chief technology officer at Jetsetter from 2009 to 2013. He met Rus Yusupov and Dom Hofmann while working at Jetsetter. Hofmann, Kroll and Yusupov founded the video hosting service Vine. Kroll worked as general manager of Vine through 2014. Vine was acquired by Twitter in 2012 (though was shut down 4 years later). After working at Twitter following the acquisition, Kroll was dismissed following "bad management" and extensive allegations of workplace sexual abuse of women. Kroll and his business partner Yusupov formed Intermedia Labs, the company behind HQ Trivia. The real-time trivia game app was launched in 2017, climbing to the top of Apple's free game app chart during the early months of 2018. Kroll and another board member forced Yusupov, who was the CEO of Intermedia Labs, out of his position and Kroll took over as CEO in September 2018.