Sarah Friar, long the CFO of Square, is leaving to join the social network Nextdoor as its CEO | Social Media

Square’s CFO Sarah Friar is stepping down to become the CEO of Nextdoor, according to the payment company’s CEO, Jack Dorsey.

In a statement issued a bit ago, he says of Friar that she “steered us through an IPO and helped build a growing ecosystem of businesses that will scale into the future.” Friar “leaves us having established a culture of entrepreneurship and discipline across the entire company. She has been an amazing leader, partner, and friend, and we are grateful for all she’s done for Square.”

Nextdoor has since released its own statement about Friar, who will assume the position in December. Quoting the company’s co-founder and outgoing CEO Nirav Tolia, the statement reads: “Sarah is one of the most highly regarded executives in Silicon Valley with an exceptionally rare mix of proven business skills, and authentic heart and soul. . . From the very beginning of our CEO search, she has been the top choice, and the board of directors and I feel exceptionally fortunate and excited for her to lead Nextdoor moving forward.”

The hire looks like a smart move by Nextdoor, the fast-growing social network that centers around neighborhoods and which, three months ago, announced that Tolia planned to step aside as soon as he found the right person to take Nextdoor “to the next level.”

At the time, Tolia had said in an email to employees that the role of CEO needed to evolve as the company evolves. He also said then that he will remain the company’s board chairman.

San Francisco-based Nextdoor has raised $285 million from investors over its eight-plus years, including from Insight Venture Partners, Benchmark, Shasta Ventures, Tiger Global Management and Kleiner Perkins. The company has soared into unicorn terrain, but it also seemingly needs to generate more revenue before it can be taken public. Toward that end, it began offering paid real estate listings roughly one year ago. The company also sells targeted ads.

Friar, often described as Dorsey’s right-hand woman at Square, grew up in Northern Ireland, the daughter of farmers. She was the first in her family to go to university, studying engineering at Oxford.

After graduating, she joined McKinsey as a business analyst in London, then Johannesburg, before moving to California in 1998 to nab an MBA at Stanford. Friar went on to spend a decade with Goldman Sachs in Silicon Valley, leaving the powerhouse bank as a managing director before spending a year with Salesforce as an SVP, then joining Square in 2012.

In addition to her work with Square, Friar sits on the boards of two powerful companies: Slack and Walmart.

Shares of Square have fallen in after-hours trading on the news.