Bydd Dr Goodall yn olynu'r Fonesig Shan Morgan fel gwas sifil uchaf Llywodraeth Cymru, sy’n gyfrifol am tua 5,000 o staff ac sydd hefyd yn brif gynghorydd polisi i’r  Prif Weinidog.
Dr Goodall will succeed Dame Shan Morgan as the most senior civil servant in the Welsh Government, responsible for around 5,000 staff, as well as the principal policy adviser to the First Minister.