Stepien received the results of the test on Friday night and is suffering from what the official described as “mild flu-like” symptoms.
Stepien was among a group of senior Trump campaign staffers who were tested, but he is the only one whose results came back positive so far. Deputy Campaign Manager Justin Clark’s test results were negative.
Prior to the shake up, Stepien served as deputy to Parscale, and before that held a senior role in Trump’s administration as White House political director.
He joined Trump’s first presidential campaign in August 2016, marking the first addition to the campaign since Conway took over as then-campaign manager and former top Trump adviser Steve Bannon took over as then-CEO.
Trump adviser Jared Kushner recruited Stepien to join the Trump campaign and the two enjoy a close relationship. A source with knowledge of the hire told CNN at the time that Bannon played a key role in bringing on Stepien.
As the national director for John McCain’s 2008 presidential campaign and New Hampshire political director on President George W. Bush’s 2004 reelection effort, Stepien brought a heavy dose of campaign experience to Trump’s operation. But he also injected some controversy into Trump’s first run.
Stepien had served as campaign manager and deputy chief of staff to New Jersey Gov. Chris Christie, a close confidant and adviser to Trump. But Christie fired Stepien in January 2014 amid the Bridgegate scandal, in which Christie aides directed the closure of lanes on the George Washington Bridge as political retribution.
This story has been updated with additional details.
CNN’s Maegan Vazquez, Jeremy Diamond and Jim Acosta contributed to this report.