Manu Tuilagi's sixth-minute try and Delon Armiatge's early second-half score saw England gain revenge for their Grand Slam-ending defeat against the same opposition back in March.
Jonny Wilkinson added two penalties and the same number of conversions, while Ireland's only points came from three Ronan O'Gara penalties.
The result means Ireland have now lost all four of their World Cup warm-up games following their previous failures against France (twice) and Scotland.
There was more bad news for the Irish in the shape of injuries to Lions back rowers David Wallace and Jamie Heaslip, both of whom left the field in the first period.
England also lost two starters to injury in Hendre Fourie - who didn't make the 30-man World Cup squad but was called to Dublin following injury to Tom Wood and Nick Easter - and 2005 Test Lion Mark Cueto.
But while both coaches will be hoping the injury setbacks don't prove too serious, there can be no doubting who will be the happier as they get ready to head to New Zealand.
As well as being delighted to finish with a first win in Dublin since 2003, Johnson will have been particularly pleased with the centre combination of Tuilagi and man of the match Mike Tindall who were playing together in midfield for the first time.
Tuilagi's power was constantly visible in attack and defence, while Tindall produced one of his most assured displays in an England shirt in recent seasons.
Ireland boss Declan Kidney can take some solace in knowing that he will be able to welcome back Lions duo Brian O'Driscoll and Rob Kearney and star flanker Sean O'Brien for the World Cup opener against the United States but four defeats in as many games will not have been on the agenda at the beginning of the month.
Having failed to make the quarter finals at the last World Cup four years ago, critics claimed Ireland were undercooked due to a lack of match practice. Kidney therefore attempted to address that issue this time around but Ireland's poor showing suggests the move could yet back fire.