Susan Russell, the executive director of Philly’s largest animal shelter, has stepped down from her post after less than a year on the job.

“It has been a truly rewarding experience to serve the animals and people of Philadelphia,” Russell said in a statement Tuesday announcing her resignation. The statement did not say why she was stepping down.

Russell took the reins at ACCT Philly on Oct. 22, a few months after her July 2018 firing by Chicago Mayor Rahm Emanuel as head of Chicago’s shelter.

Her start at ACCT had a controversial beginning after claims that Russell “warehoused” dogs and made them more dangerous followed her to Philly, although she denied warehousing dogs. In Chicago, Russell was said to have been reluctant to euthanize dogs in shelters, leading to overcrowding.

Like ACCT Philly, Russell’s Chicago shelters were open-admission — meaning no animal could be turned away, leading to more overcrowding issues.

At the start of her tenure in Philly, Russell said she aimed to turn the organization into a “no-kill” shelter, meaning all healthy animals would find a home.

But the shelter has gone through its share of challenges over the last year, including a severe case of kennel cough that led to dog deaths and forced ACCT to temporarily suspend adoptions. Adoptions were reopened after a month, with a free-adoption weekend to combat overcrowding.

Still, the shelter increased its rate of release for dogs and cats this year, Russell said in the statement.

“While there have been some challenges, together we have also had many successes. I was proud to be a part of ACCT’s first Gala, and to increase live release rates — more than 90 percent for dogs and roughly 88 percent for cats in the first half of 2019," she said.

ACCT Philly said it would immediately begin the search for a new executive director.

A spokesperson for the organization said no further information was available about Russell’s resignation or what prompted it.