English, who was the sole contender for the job, announced Social Housing Minister Paula Bennett as the deputy leader, following a special caucus meeting of the ruling centre-right National Party.
English, who will be sworn in later in the day, has already lined up senior cabinet minister Steven Joyce, the minister for economic development, to replace him in the finance ministry.
He is expected to announce further cabinet changes in the coming weeks and has also signalled a "stocktake" on policy.
"I am both excited and humbled by this opportunity," English, who comes from a conservative, Catholic family in New Zealand's south, told reporters after the meeting.
English, who 13 years ago oversaw a disastrous election loss for the National Party to the centre-left Labour Party, takes the reins of a country in good economic shape compared to much of the developed world.
On Monday, Moody's said it expects New Zealand to remain among the fastest growing of triple-A rated economies.
English has held several ministerial posts across education, health and finance since he joined parliament in 1990.
As finance minister, his key policies included moves to partly privatize several state-owned energy firms and Air New Zealand, cutting personal tax and corporate tax rates and increasing the goods and services tax. (Reporting by Swati Pandey and Charlotte Greenfield; Editing by Richard Pullin)
source: news.abs-cbn.com
