Miller unveiled the plan at Express Scripts' annual client conference in Florida, the same conference where he first previewed taking a tough stance against Gilead Science's high-priced hepatitis C drug Sovaldi in order to secure better pricing on a competitor's hepatitis drug.
The move is a departure for the nation's largest pharmacy benefits management (PBM) firm, which has no retail outlets of its own, unlike rival CVS Health.
Miller did not name which pharmacies would be part of the new program, saying he and his staff are looking to line up chains and independent pharmacies by year's end.
"It's such a rapidly growing problem," said Miller. "We have got to change the paradigm, and we think pharmacies are the way to do that."
Express Scripts has taken a public stance on combating drugmakers when it comes to high costs, but its tough negotiating tactics have also put it at odds with its partners at times.
Four years ago, Walgreens and Express Scripts went to court over a contract dispute. The issue was resolved and Walgreens is now the PBM's preferred pharmacy network for Medicare drug plans.
Currently, Express Scripts is in a contract dispute with its largest customer, Anthem.
Some analysts question whether Express Scripts can survive as a standalone PBM long-term if it loses Anthem as a customer. The nation's second-largest insurer says it is now considering the possibility of bringing its pharmacy services in-house, after having sold its PBM business to Express Scripts seven years ago.
Anthem CEO Joseph Swedish told analysts during his company's earnings conference call this week that re-establishing its pharmacy benefit unit is one of the possible options if things aren't resolved.