Long-time Sinn Féin MLA John O'Dowd has been appointed interim infrastructure minister, replacing the unseated Nichola Mallon.
Mr O'Dowd was appointed by Michelle O'Neill and will serve in the portfolio until a new Executive can be appointed.
The new minister is familiar with the demands of holding an Executive post, having served as education minister from 2011-2016.
He also acted as interim Deputy First Minister in 2011 when Martin McGuinness was running for the Presidency of Ireland.
Mr O'Dowd had previously challenged Ms O'Neill for the vice-presidency of the party, however he has now been appointed by her to the vacant ministerial post.
The Upper Bann MLA was able to be named interim minister as Sinn Féin had the next choice of minister after winning the highest number of seats in the election on May 5
In the Stormont system, ministerial posts are allocated based on the number of seats won by each party in the Assembly election.
The appointment is interim as the Executive continues in interim form following the collapse in February.
Until the Assembly sits in full again and the parties agree to form a new Executive, new ministers cannot take up full-time positions.
Because it is an interim appointment, the SDLP had the option of nominating a replacement for Mrs Mallon.
However, the SDLP decided against nominating a new minister to the post.
SDLP leader Colum Eastwood said that his party did not have a mandate for government, and would not be part of a "zombie Executive" of interim ministers.