Smurfit, whose father, Michael, was chief executive of the company before McGann, has been chief operations officer since 2002 and has worked in various parts of the business in Europe and the US since being appointed a director in 1989.
Earnings before interest, tax, depreciation and amortisation declined to €266m in the opening quarter despite revenue climbing 2% to more than €1.9bn.
Pre-tax profits fell to €98m from €104m in the same period in 2014.
The Irish packaging company said its European business continued to perform strongly over the opening three months over the year with box volumes up 3% and stronger sheet volumes.
Smurfit’s business in the Americas followed suit with a 16% increase in volumes which was delivered on the back of organic growth and acquisitions.
Its Venezuelan operations struggled however, as currency movements weighed against it.
“Against the backdrop of a more positive European business environment, and improvements in our operational performance in the Americas, we expect to deliver earnings growth year-on-year.
“As we build the business through our differentiated offering and new investments, we remain committed to our core financial and operational disciplines,” Mr McGann said.