"Not all Democrats are the same," she tweeted, alongside the news that Emanuel joined boutique investment bank Centerview.
Emanuel, a longtime Democratic operative, left office in May after serving as the Windy City's mayor for two terms. He had previously served as former President Barack Obama's chief of staff, among other positions.
Emanuel will start at Centerview Partners in July, The Wall Street Journal reported. The Journal reported that Emanuel fielded offers from other financial services firms and might even get his own talk show.
Ocasio-Cortez denounced Emanuel at a time when the Democratic Party seemed to face a growing, progressive wing that demanded sweeping reforms affecting Wall Street and the economy in general.
She teamed up with Sen. Bernie Sanders, I-Vt., and Sen. Elizabeth Warren, D-Mass., as both used economic inequality as part of their campaigns for the 2020 Democratic presidential nomination.
She and Sanders proposed a plan that would cap interest rates at 15 percent, a measure she touted before her tweet knocking Emanuel on Wednesday.
Warren, who proposed a massive jobs plan that included a tax on corporate profits, joined Ocasio-Cortez in pressing Treasury Secretary Steve Mnuchin over his ties to Sears and a lawsuit filed against its former chairman.