Patricia Mitchell, who led an expansion of the Ordway Center for the Performing Arts while bringing calm, stability and wit to a once-fractious venue, announced Thursday that she will retire as president and CEO.

“If these jobs came in any size other than ‘extra large,’ I’d go on wearing this one forever,” she said Thursday evening. “But they don’t, and life is fleeting.”

Mitchell, who has served since 2007 as the St. Paul multi-arts center’s president and CEO, turns 68 in August. She will stay until December while the board conducts a national search for her replacement.

She leaves a legacy both as peacemaker and builder. In February, the Ordway opened a 1,100-seat, $42 million concert hall that was greeted with plaudits for Tim Carl’s elegant, simple architecture and its exquisite acoustics. Serving as principal home of the St. Paul Chamber Orchestra, it complements an adjoining 1,900-seat theater where operas, musicals and major stage shows are presented.

A joint effort by the Ordway and its three “arts partners” — the SPCO, Schubert Club and Minnesota Opera — the hall was completed in a collegial way that was a far cry from the beginning of Mitchell’s tenure, when tenants competed fiercely for space in the larger hall. Her no-nonsense style smoothed out the process and stopped the sniping.

“Patricia is a genuinely great colleague,” said Schubert Club director Barry Kempton. “She has a strong sense of what the Ordway is about and could be, and has been enthusiastic in working with us to achieve things together. She’ll be a very hard act to follow.”

That sentiment is widely shared.

“Patricia has taken the Ordway to a great place and she’s much beloved, both for her leadership and her witty, collaborative style,” said Laura McCarten, vice chairwoman and incoming chairwoman of the Ordway’s board. “She’s moved us forward with programs that expand the Ordway and connects it with diverse audiences. She’s really been a transformational leader and we’re going to miss her.”

Mitchell’s eight years at the Ordway cap a half-century career in arts administration. She has held executive posts at the San Francisco Opera, the Los Angeles Opera, the Hollywood Bowl and the Los Angeles Philharmonic, where she was instrumental in the building of Disney Concert Hall. Before going West, she served as community relations director for the Guthrie Theater.

Mitchell believes that this is the right time to move on, both for her and for the organization that she loves.

“Organizations have arcs, and this is a really good time for the life cycle of Ordway,” she said. “It’s 30 years old, and will be here for another 30 and another 30. The new concert hall provides the next leader with a great opportunity to take the Ordway to another level.”

When she leaves, she plans to “read books in the daytime, and find out what it means to retire.”