Arun was India's bowling coach during Shastri's previous tenure as Team Director and the latter had insisted on his appointment in his soon-to-start second stint with the Indian team.
The decision to appoint Arun, on a two-year contract, was taken after Shastri met the Committee of Administrators (CoA) and BCCI officials, including acting President C K Khanna and Secretary Amitabh Chaudhary.
"I was in England and was watching tennis (the Wimbledon). I was very clear in my mind what my core team would be, what you just heard is my core team," Shastri said after Chaudhary announced the appointment in a press conference.
Besides, the BCCI also decided to retain Sanjay Bangar as assistant coach and R Sridhar as fielding coach till the 2019 ODI World Cup.
Also Read
"Patrick Farhad also continues as physio...All of them are part of the team for two years until the closure of next World Cup," Chaudhary said.
Arun's appointment marks a complete u-turn for the BCCI, which had named Zaheer Khan as bowling consultant initially before clarifying that it was for specific overseas tours.
There is no clarity on Rahul Dravid's position as batting consultant either.
"All depends on their availability, it depends on individuals, the number of days they want to give but their inputs will be invaluable and they are most welcome," he added.
Chaudhary, on his part, said there was never any confusion on Dravid and Zaheer despite the obvious flip-flops by the BCCI.
Shastri thanked the Cricket Advisory Committee -- comprising Sachin Tendulkar, Sourav Ganguly and VVS Laxman -- for picking him for the high-profile job.
"I would like to thank the CAC because it is a privilege and an honour to be India's coach. And I would like to thank the CAC for considering me worthy enough for the job," he said.
Neither Zaheer, nor Dravid have yet spoken about the lack of clarity regarding their positions.
Disclaimer: No Business Standard Journalist was involved in creation of this content