WASHINGTON — The CEO of the Democratic National Committee is leaving after less than a year on the job, NBC News has learned.

Veteran Democrat operative Jess O’Connell took the helm of the DNC last May with a mandate to help newly installed Chairman Tom Perez turn around a troubled party organization that was struggling after years of neglect and a brutal 2016 that included accusations of favoritism in the primary between Hillary Clinton and Bernie Sanders, the hacking of internal emails, and the loss to President Donald Trump.

O’Connell will leave the party stabilized, if not yet fully recovered, after wins last year in Virginia and Alabama, and her decision to leave is a personal one, a DNC official told NBC News, timed to cause minimal disruption ahead of November's midterm elections.

10 PHOTOS DNC Media Tent Protest See Gallery DNC Media Tent Protest A supporter of Senator Bernie Sanders, an independent from Vermont, holds a sign reading 'Actions Speak Louder Than Words' while demonstrating inside the media tent during the Democratic National Convention (DNC) in Philadelphia, Pennsylvania, U.S., on Tuesday, July 26, 2016. Democrats began their presidential nominating convention Monday with a struggle to fully unite the party, following a dramatic day of internal squabbling and protests. Photographer: Andrew Harrer/Bloomberg via Getty Images Supporters of Senator Bernie Sanders, an independent from Vermont, hold signs while demonstrating inside the media tent during the Democratic National Convention (DNC) in Philadelphia, Pennsylvania, U.S., on Tuesday, July 26, 2016. Democrats began their presidential nominating convention Monday with a struggle to fully unite the party, following a dramatic day of internal squabbling and protests. Photographer: Andrew Harrer/Bloomberg via Getty Images UNITED STATES - JULY 26: Republican nominee Donald Trump appears on a monitor as supporters of Sen. Bernie Sanders, I-Vt., stage a sit-in of the media tents after walking out of the Wells Fargo Center in Philadelphia, Pa., on the second day of the Democratic National Convention, July 26, 2016. (Photo By Tom Williams/CQ Roll Call) A supporter of Senator Bernie Sanders, an independent from Vermont, holds a sign reading 'A Vote For Hilary Is A Vote For Trump' while demonstrating outside the media tent during the Democratic National Convention (DNC) in Philadelphia, Pennsylvania, U.S., on Tuesday, July 26, 2016. Democrats began their presidential nominating convention Monday with a struggle to fully unite the party, following a dramatic day of internal squabbling and protests. Photographer: Andrew Harrer/Bloomberg via Getty Images Supporters of Senator Bernie Sanders, an independent from Vermont, touch hands through the glass of the media tent while demonstrating during the Democratic National Convention (DNC) in Philadelphia, Pennsylvania, U.S., on Tuesday, July 26, 2016. Democrats began their presidential nominating convention Monday with a struggle to fully unite the party, following a dramatic day of internal squabbling and protests. Photographer: Andrew Harrer/Bloomberg via Getty Images Supporters of Senator Bernie Sanders, an independent from Vermont, wears a sticker over her mouth while demonstrating outside the media tent during the Democratic National Convention (DNC) in Philadelphia, Pennsylvania, U.S., on Tuesday, July 26, 2016. Democrats began their presidential nominating convention Monday with a struggle to fully unite the party, following a dramatic day of internal squabbling and protests. Photographer: Andrew Harrer/Bloomberg via Getty Images UNITED STATES - JULY 26: Supporters of Sen. Bernie Sanders, I-Vt., stage a sit-in of the media tent after walking out of the Wells Fargo Center in Philadelphia, Pa., on the second day of the Democratic National Convention, July 26, 2016. (Photo By Tom Williams/CQ Roll Call) UNITED STATES - JULY 26: Bernie Sanders delegates and supporters stage a walk out and protest at the media tents outside the Democratic National Convention in Philadelphia on Tuesday, July 26, 2016. (Photo By Bill Clark/CQ Roll Call) PHILADELPHIA, PA - JULY 26: Police watch protesters near the Wells Fargo Center on the second day of the Democratic National Convention (DNC) on July 26, 2016 in Philadelphia, Pennsylvania. The convention is expected to attract thousands of protesters, members of the media and Democratic delegates to the City of Brotherly Love. (Photo by Jeff J Mitchell/Getty Images) PHILADELPHIA, PA - JULY 26: Police watch protesters near the Wells Fargo Center on the second day of the Democratic National Convention (DNC) on July 26, 2016 in Philadelphia, Pennsylvania. The convention is expected to attract thousands of protesters, members of the media and Democratic delegates to the City of Brotherly Love. (Photo by Jeff J Mitchell/Getty Images) Up Next See Gallery Discover More Like This HIDE CAPTION SHOW CAPTION of SEE ALL BACK TO SLIDE

But O'Connell's departure comes just months after the DNC ousted its finance director following a period of weak fundraising, as well as a shakeup last year that reignited tensions with Sanders' allies. Still, the party has found itself subject to fewer negative headlines of late as fundraising started to improve and vacancies are filled.

In a farewell email to DNC staff on Monday night, O’Connell thanked them and said she was proud of their work, while not offering a specific reason for her departure.

Perez quickly launched a search for a new CEO. O’Connell, who previously held a top job at the Democratic women's group Emily’s List, will help with the transition after she leaves next month.

The CEO is the DNC's top staffer, overseeing day-to-day operations and political strategy at party headquarters, often while the chairman is away raising money, stumping for candidates and appearing in public.

"Rebuilding the party will take time. While it isn't an easy task, we developed a strategy, we implemented it, and we won races up and down the ballot in 2017," O’Connell said in a statement. "While I've made the decision to pass the baton, our work remains far from over and under Tom Perez's leadership and direction, our party will continue to build on the progress we've made in 2017."

Perez praised O'Connell for her help during his first year on the job, when the DNC was often defending itself from attacks while also trying to expand its mission to include year-round organizing.

"Jess O'Connell joined the DNC at a time when our party needed it the most," Perez said in a statement. "She helped build our 'Every Zip Code Counts' strategy, oversaw unprecedented programming and support for state parties and campaigns, renewed our focus on data and technology, and helped lead us to 100+ victories in elections all across the country in 2017. Jess laid the groundwork for an infrastructure to win in 2018, 2020 and beyond."

O'Connell had a senior role in Hillary Clinton's 2008 presidential campaign and was one of the campaign officials who urged the then-senator to fire an aide after a female employee lodged a harassment complaint, but was overruled by Clinton, according to recent reports in BuzzFeed and The New York Times.

7 PHOTOS DNC Hillary speech protesters See Gallery DNC Hillary speech protesters Activists hold a banner against Hillary Clinton amid protest outside the Wells Fargo Center on the final day of the Democratic National Convention in Philadelphia, Pennsylvania, U.S., July 28, 2016. REUTERS/Dominick Reuter Bernie Sanders supporters protest U.S. Democratic presidential nominee Hillary Clinton at the Democratic National Convention in Philadelphia, Pennsylvania, U.S. July 28, 2016. REUTERS/Lucy Nicholson Protesters wearing masks of presidential candidates Hillary Clinton and Donald Trump march with a group of cannabis advocates down Broad Street toward the Wells Fargo Center on the final day of the Democratic National Convention in Philadelphia, Pennsylvania, U.S., July 28, 2016. REUTERS/Dominick Reuter A former Bernie Sanders delegate wears a Hillary Clinton presidential campaign sticker over his mouth as he protests during the third session at the Democratic National Convention in Philadelphia, Pennsylvania, U.S. July 27, 2016. REUTERS/Carlos Barria Pennsylvania State Troopers face off with Bernie Sanders supporters and delegates outside of the convention arena after they stormed off the convention floor in protest when Hillary Clinton won the Democratic presidential nomination during the second day at the Democratic National Convention in Philadelphia, Pennsylvania, U.S. July 26, 2016. REUTERS/Mark Kauzlarich Signs of support for Hillary Clinton and protest signs are seen on the fourth and final day of the Democratic National Convention at Wells Fargo Center on July 28, 2016 in Philadelphia, Pennsylvania. / AFP / Robyn BECK (Photo credit should read ROBYN BECK/AFP/Getty Images) TOPSHOT - A protester stands with his mouth gagged with the American flag at a rally of support for former Democratic presidential candidate Bernie Sanders and protest against Hillary Clinton's nomination during the 2016 Democratic National Convention on July 27, 2016 in Philadelphia, Pennsylvania. / AFP / Patrick T. Fallon (Photo credit should read PATRICK T. FALLON/AFP/Getty Images) Up Next See Gallery Discover More Like This HIDE CAPTION SHOW CAPTION of SEE ALL BACK TO SLIDE

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