Ishant paid rich tributes to his "first idol" and "very dear friend" Zaheer in a column for the Board of Control for Cricket in India's (BCCI) website.
The 37-year-old Zaheer bid adieu to international cricket on Thursday after playing for 14 years. He will however sign off from all forms of cricket after next year's Indian Premier League (IPL) with Delhi Daredevils.
"I was at the Feroz Shah Kotla, playing a Ranji (Trophy) game yesterday. When I got off the field, I heard the news that Zaheer Khan has announced his retirement from international cricket. It brought back a deluge of emotions.
"I went home and started to reminisce all the moments I have spent with him in the Indian team - all those times I bowled with him and the memories I shared with him in the dressing room," this is how Ishant start off his tribute to the left-arm pacer.
"I looked back at my initial days as an international cricketer and how Zak pa (Zaheer Khan) helped me to become the bowler I am today. He was my first idol, a role model who later became a very dear friend," the 27-year-old Ishant wrote.
"No one knows how big an influence Zak pa has been in my life. He groomed me as a bowler. He took a young, raw fast bowler under his wing and made me a mature bowler I am today. I owe so much to Zak pa, and I cannot thank him enough for all that he has done for me," he added.
Ishant, who has so far played 65 Tests, 76 ODIs and 14 T20Is for India, recalled how Zaheer was always there for him to help during matches. Ishant made his Test debut, playing with Zaheer, against Bangladesh in 2007.
"A very good example of what difference Zak pa made in my bowling was the 2008 Border-Gavaskar Series. I picked up 15 wickets and was declared the Man of the Series. Why? Because of Zak pa.
"In India a pace bowler's biggest strength is the reverse swing. At that time, I could only reverse the ball in. Zak pa taught me how to reverse the ball away from the batsman - simple things like how your hand should be and where the seam should face. It was a very small thing but it made a huge difference," he said.