Runnicles began his operatic career as a singers' coach and assistant conductor in Mannheim, Germany.[2] He became Generalmusikdirektor of the city of Freiburg, Germany in 1989. Referring to the 10 years he spent in Germany, Runnicles has said
"I have to breathe this air, this Wagnerian air. It was life-changing and that love affair with Wagner led to what was influenced by him: the Bruckner, the Mahler."[3]
In the US, Runnicles served as Music Director and Principal Conductor of the San Francisco Opera from 1992 to 2009.[12][13][14] Runnicles was principal guest conductor of the Atlanta Symphony Orchestra from September 2001 through the 2021-2022 season.[15][16][17] From 2001 to 2007, he was principal conductor of the Orchestra of St. Luke's. Runnicles had been offered the title of music director of the Orchestra of St. Luke's, but he declined the title.[18] He became Music Director of the Grand Teton Music Festival in September 2005, having been appointed that August.[19] His Grand Teton contract was extended through 2011,[20] and subsequently to 2019.[21]
Runnicles first conducted the BBC Scottish Symphony Orchestra (BBC SSO) in 2001.[1] In October 2007, the BBC SSO announced the appointment of Runnicles as their next Chief Conductor in September 2009, for an initial contract of three years.[22][23] The BBC SSO appointment marked Runnicles' first principal post with a British orchestra.[24] In September 2011, the BBC SSO extended his contract as chief conductor through 2015.[25] In October 2014, the orchestra reported the scheduled conclusion of Runnicles' tenure as chief conductor in September 2016.[26] His final concert as the BBC SSO's chief conductor was on 28 August 2016,[27] and he now has the title of Conductor Emeritus of the BBC SSO.
In October 2007, the Deutsche Oper Berlin announced the appointment of Runnicles as their next Generalmusikdirektor, effective August 2009, for an initial contract of five years.[28] In December 2016, the company announced the newest extension of Runnicles' contract with the Deutsche Oper Berlin until 2022.[29] In November 2020, the Deutsche Oper Berlin announced the most recent extension of Runnicles' contract as its GMD, through 2027.[30] In September 2023, the Deutsche Oper Berlin announced that Runnicles is to stand down as its GMD at the close of the 2025–2026 season, one season earlier than the most recent contract extension, at Runnicles' own request.[31] From 11 May to 2 June 2024, Runnicles conducted the full season of the Richard Wagner Tetralogy, Der Ring des Nibelungen at Deutsche Oper.[11][32]
In December 2022, Runnicles first guest-conducted the Dresden Philharmonic. In December 2023, the Dresden Philharmonic announced the appointment of Runnicles as its next chief conductor, effective with the 2025-2026 season. He is scheduled to serve as chief conductor-designate for the 2024–2025 season.[33]
Runnicles has two daughters, Ashley and Tamara,[2][34] from his previous marriage to South African violist Elizabeth Prior,[35] as well as an older daughter, Alexandra, from a previous relationship. His second marriage is to the Canadian Pilates teacher Adelle Eslinger.[36]