[1] His initial musical training was as a cellist,[2] and he subsequently played cello in the Edinburgh Youth Orchestra.
[4] He subsequently became associate conductor of the Royal Scottish National Orchestra (RSNO).
In November 2015, the Staatsorchester Rheinische Philharmonie announced the appointment of Walker as its chief conductor, effective with the 2017–2018 season.
[7] In June 2019, Opera North announced the appointment of Walker as its next music director, effective with the 2020–2021 season.
[8] In February 2020, the Staatsorchester Rheinische Philharmonie announced that Walker is to stand down as its chief conductor at the close of the 2021-2022 season.