"Baz [McCullum] is the most optimistic person I have ever met in my life,” Iyer said. “I remember there was a game where we were like 60-odd for 7 wickets and still needed around 80 more to win.
“He came in the time-out to speak to us and said, 'Just 13 more sixes to go.' It's not easy, but these small things make you believe that it is still possible."
McCullum left KKR after the 2022 season to become England's Test coach.
"He is very composed and poised in the dugout and doesn't let the pressure affect anyone," Iyer continued.
“One of the best things about him is that he lets everyone play their natural game and just go out there and enjoy the game."
McCullum as coach
McCullum has been named head coach of the England Test team, succeeding Chris Silverwood. He will be in charge of an international cricket team for the first time.
To replace McCullum, KKR hired Ranji Trophy-winning coach Chandrakant Pandit. McCullum was a member of KKR in the inaugural edition in 2008, when he hit a swashbuckling 158 in the first-ever IPL match.
"I have loved it. It's been three years now, and all three years have been in bubbles," McCullum said.
"It gives opportunities to some incredibly good talent. And as a coach to be able to be a part of it and give some of the guys the freedom to go out there and play with a positive attitude is something I'm forever grateful for."
Dinesh Karthik and McCullum formed a partnership as KKR coach and captain during their time with the team in the IPL.
When asked what kind of work ethic McCullum instilled in the team, Karthik described it as a "relaxed" one.
"It will be a very relaxed dressing room,” Karthik said. “I've seen that he is somebody who focuses a lot on playing a lot of sports off the field and off the field having a lot of fun as well."
Iyer under national coach Rahul Dravid
In a recent interview, Iyer also discussed the differences in coaching styles between national team coach Rahul Dravid and McCullum. Iyer said Dravid taught him a lot of things, especially about communication.
"Rahul Dravid sir is a legend and a stalwart of the game,” Iyer said. “We all know what he has done for Indian cricket. But the thing I liked about him is the communication regarding role clarity.
“The way he communicates with players, the way he handles players is something I am very fond of."
Iyer's performance in 2022 was rather disappointing, recording only 182 runs in 12 matches at a depressing 16.55 average. The all-rounder was subsequently dropped from the West Indies and Zimbabwe series.
Iyer last played for India in a T20I International against Sri Lanka in February. He was omitted from the Men in Blue roster for the upcoming Asia Cup.