But her biggest responsibility may be as associate to Earthquake Recovery Minister Gerry Brownlee. She is expected to spend a lot of time on the ground in Christchurch as the rebuild enters a critical phase.
National's most highly ranked woman, Judith Collins, got what she wanted, taking the Justice portfolio from retiring minister Simon Power, and will front the sensitive issue of ACC reform this term.
National has promised to introduce competition in the work account.
Mr Joyce has added Economic Development, plus Employment and Skills, and Science and Innovation to his Tertiary Education portfolio.
His unwritten role will be to provide strategic co-ordination not just among his own portfolios but to other ministers with sectoral interests, such as energy and resources, to help lift economic performance.
Mr Joyce's leap from No14 last term to No4 now, Mr Key said, "reflected the reality of what has been a tremendous first term" by him.
Mr Brownlee has picked up Transport from Mr Joyce. Fisheries and Aquaculture have been folded in with Agriculture and Biosecurity to form a new portfolio of Primary Industries.
Labour Minister Kate Wilkinson has been pushed up the rankings by other movements rather than having been promoted. It would have been inappropriate to move her out of the Labour portfolio while the Royal Commission of Inquiry into the Pike River mining disaster was ongoing.
After doing battle with teacher unions for a term, especially over National Standards, Anne Tolley has lost the Education portfolio and was moved down to allow for fresh blood.
She has taken on the Police portfolio and is seen as tough enough to be taking on Corrections, which Judith Collins has kept under control.
Outside cabinet Mr Key has promoted junior whip Jo Goodhew to take over the work of Tariana Turia as Minister of the Community and Voluntary Sector.
Senior whip Chris Tremain was promoted to a ministerial post outside cabinet as well, leaving two or three whips roles to fill next week to manage the caucus of 59.
Michael Woodhouse and Simon Bridges are front runners.