Aircel chief executive officer (CEO) Kaizad Heerjee has resigned from his position, marking the exit of a man widely credited with turning around the mobile phone operator before it ran into financial stress as competition intensified with the entry of Reliance Jio.

Heerjee was nominated as the CEO of Aircel towards the end of 2013 after that post lay vacant for almost eight months. He was chief operating officer (COO) under Sandip Das, who left his position as Aircel CEO to join Mukesh Ambani’s Jio.

Heerjee had joined Aircel from Malaysian operator U Mobile a year before he became CEO.