Walsh returned to the Power in September 2013 as midfield manager after spending five seasons at West Coast in the role of strategy and innovations coach.
He had previously served at Alberton as an assistant coach from 1999 to 2008.
Port Adelaide chief executive Keith Thomas congratulated Walsh on his appointment.
“On behalf of everyone at Port Adelaide I wish Phil all the very best in his new role at the Crows,” Mr Thomas said.
“Although we are disappointed to lose a coach of Phil’s ability we respect his desire to be a senior coach and wish him luck with the position.
“As a club we can be proud that another one of our people is admired so much that they’ve been recruited by a competitor for a senior coaching role.
“We are about growing our people both personally and professionally and we are now highly respected in the industry for the way we develop our staff.”
Mr Thomas said the club would now commence a nation-wide search to fill the position vacated by Walsh.
