"As the competitive landscape continues to evolve, it is all the more critical that we represent credit unions with a unified voice."
Murphy will leave the league effective June 1, 2017.
David Frankil will take the helm of the league on June 27.
The Phoenix-based Mountain West, which represents credit unions in Arizona, Colorado and Wyoming, buys in to the back office CUSO.
Industry consolidation trends and declining revenue claim another small league.
Member credit unions gain membership optionality in 2017.
Restated bylaws allow credit unions to join CUNA without joining a league and removes other dual membership language.
Longtime CUNA EVP Susan Newton, who led the AACUL, will leave the trade association in a few months.
Newly-formed Kansas-Missouri league plans to select its first CEO in Q1 2016.
Utah is the eighth league to publicly support dual membership. Four league boards have voted to allow membership choice.