Alfredo Sáenz has resigned as Santander vice-chairman and chief executive.
Senior executive vice president and head of the global insurance, asset management and private banking division Javier Marín has been appointed as Sáenz’s successor.
The Times reports that Sáenz had been involved in a legal battle over whether his criminal conviction should disqualify him from the chief executive position.
He received a suspended sentence in 2009 for making false accusations against shareholders in Santander-owned Banesto bank.
Sáenz joined Grupo Santander in 1994, when it acquired Banesto through an auction. He was executive chairman of the unit until 2002, when he was named vice chairman and chief executive of Banco Santander.
This month, Santander reported a 26 per cent fall in profit over the first three months of 2013. The Spanish bank reported profits of €1.2bn (£1bn) for the first quarter, down from €1.6bn from the same period in 2012.