Mikael Ohlsson, leader since 2009, had informed the board he wished to step down after 34 years with Ikea.
The reshuffle came as the firm pledged to speed up its store expansion pace as part of a bid to further boost growth.
In a joint telephone interview with Ohlsson, Agnefjall said that the privately-held firm would aim to boost growth further.
Ikea would from 2014-2015 increase the pace of new store openings to 20-25 per year, compared to seven in 2010/2011 and 11 in 2011/12.
Ohlsson said Ikea grew turnover by about seven per cent in its fiscal year to August 31 on volume growth of about eight per cent, which would mean sales hit a record €27bn (£22bn).