The move came after Connells completed its £130m takeover of Countrywide earlier this week.
Curran (pictured) joined Countrywide in 2015 from Lloyds Banking Group where he was director of strategic partnerships having been with the group for more than 20 years.
Countrywide confirmed the move to Mortgage Solutions and thanked Curran for his work.
It said: “Now the transaction has completed, we can confirm that Peter Curran, managing director – financial services has left Countrywide.
“We want to record our thanks for his contribution to the business and wish him well in his future career.”
Mortgage Solutions has asked Countrywide if any other employees have left the business and has also contacted Curran.
On completing the deal, Connells said management from both companies would oversee the daily operations of Countrywide and the integration of the businesses.
However, Countrywide group managing director Paul Creffield will transition to a part-time role ahead of his retirement.
