Timing is everything in music, and Donald Runnicles’s decision 12 years ago to become Principal Guest Conductor-designate of the Atlanta Symphony Orchestra and join Music Director-designate Robert Spano in a novel creative partnership has been serendipitous for all parties.

“I’m delighted and grateful to be part of what I consider to be a vital and groundbreaking collaboration,” Mr. Runnicles said at the time, and the creative partnership has certainly been a trailblazer, bringing dynamic programming and guests and today’s brightest young composers to Atlanta Symphony Hall and dramatically energizing the Orchestra’s presence in the community.

Throughout his tenure in Atlanta, the career trajectory of the acclaimed maestro has soared. Mr. Runnicles’s first Orchestra recording, Orff’s Carmina Burana, was released in 2003 and subsequent releases of Mozart’s Requiem, Beethoven’s Ninth Symphony, and a Brittania album were all well received. His visits with the Chorus to perform with the esteemed Berlin Philharmonic were acclaimed and led to the Chorus’s burgeoning global reputation as a major force in the operatic and symphonic arenas. Not to mention that his conducting appearances at Atlanta Symphony Hall have been increasingly popular with Orchestra patrons. Mr. Runnicles’s involvement with the Atlanta Symphony organization has been tremendous, and this year his relationship with Orchestra will extend even further, as he will lead a reading session with the Atlanta Symphony Youth Orchestra for the first time at the end of the month.

Over the past few years, Mr. Runnicles’s focus has shifted abroad as the music director of the Deutsche Oper Berlin and chief conductor of his homeland pride and joy, the BBC Scottish Symphony Orchestra.

The move to Berlin, where he now resides, “constituted a huge shift in my personal life,” recalled Mr. Runnicles. “Yet I relish being at the helm of one of the most storied opera houses in the world, which annually performs all of the major German romantic operas — Wagner and Strauss, not to mention Mozart, Berlioz, Debussy and Janacek. The orchestra also gives symphonic concerts and has a chamber music series. Life is busy and diverse!”

Yet his importance to the players and singers here is unquestioned and his two appearances during the 2011-12 season are indispensable: conducting the Beethoven “Eroica” Symphony No. 3 and Britten’s Violin Concerto, featuring the fine Canadian virtuoso James Ehnes, January 19-22; and with the Chorus, Mahler’s “Resurrection” Symphony No. 2, January 26/28.

Mr. Runnicles is especially looking forward to reuniting with the Atlanta Symphony Orchestra Chorus, in his view “one of the finest in the world. There is a phenomenal discipline to their singing. To listen to their warm-up routine is still awe-inspiring!” Throughout his Atlanta tenure, his relationship with the Chorus has blossomed. In his 11 years as Principal Guest Conductor, Mr. Runnicles and the Chorus have annually performed in Atlanta, as well as with the Berlin Philharmonic on three separate occasions.

“We really enjoy working with Donald,” said Nick Jones, a longtime member of the Chorus and the Orchestra’s former program annotator. “[His] fluid conducting style, his songful interpretations, his idiosyncratic left-handed baton … we love his piercing Scottish gaze and his lilting brogue. We accompanied him to Germany three times, allowing us to build a terrific relationship with the Berlin Philharmonic. And of course, we joyfully anticipate each time he works with us in Atlanta.”

Reminiscing about the Chorus’s performance of the Berlioz Requiem with the Berlin players in 2008, Mr. Runnicles said, “When the Chorus began to sing without accompaniment, the orchestra all turned around. The collective look on their faces was one of the most moving things I have ever seen.” Most recently, Mr. Runnicles and the Chorus performed Brahms’s A German Requiem with the German orchestra in 2009.

And the creative partnership? “It’s hard to believe 10 years of collaborating with Robert and this Orchestra have gone by so quickly,” Mr. Runnicles said. “It’s been a unique, joyous, utterly inspiring synergy that Robert and I have enjoyed, and I’ve loved and treasured the partnership. The challenges and achievements over the years have been considerable. What a joy and privilege to belong to the Atlanta family.”

For more than a decade, Mr. Spano and Mr. Runnicles have helped shape musical perspective and programming within the Atlanta Symphony and throughout the country. Under their leadership, the Orchestra has been acknowledged as a hub of creativity through performances, presentations, and learning forums, all inspired by the work of this dynamic artistic team.

“The excitement and fulfillment of working with Robert and the Atlanta Symphony Orchestra deepens for me each year,” explained Mr. Runnicles.

And the feeling is mutual. Of the creative partnership, Mr. Spano said, “To have been able to have this journey here with Donald has been one of the joys of my life. We have a wonderful professional friendship and I’m very blessed.”

“With Robert and with Donald, it’s sometimes easy to forget — until we read about them in the New York Times or some other place — that these are two international superstars who are completely at home here in Atlanta,” said Atlanta Symphony Orchestra President Stanley E. Romanstein. “We’re incredibly fortunate to have him.”