Baroness Morgan was confirmed as first minister by a vote of Senedd members on Tuesday morning.
The Welsh parliament was recalled from summer holiday for a special sitting to vote for a new first minister after the resignation of Vaughan Gething as Welsh Labour leader.
The new first minister earned 28 votes, Welsh Conservative leader Andrew RT Davies secured 15 votes, and Plaid Cymru leader Rhun ap Iorwerth received 12 nominations.
Mr Gething faced questions about a disputed £200,000 donation and the firing of a minister, before four members of his administration resigned.
The battle to succeed Mr Gething was scheduled to last until September.
However, Baroness Morgan, who has been Wales’ health secretary since 2021, won the subsequent leadership contest unopposed.
She ran on a joint ticket with rural affairs secretary Huw Irranca-Davies, whom she intends to appoint as her deputy.
The duo has promised “strength, stability, and unity,” with an emphasis on “improving the things that matter most” for people across the country.
