[3] Mueller is also the CEO of the for-profit publicly traded Grand Canyon Education Inc that provides services to GCU.

Mueller also held executive positions with the University of Phoenix Online including CEO, chief operating officer, and senior vice president.

[8] At the University of Phoenix he rose to a leadership role, as president, his team designed what the department of Education later termed as "predatory".

[10] Mueller finished fourth in the Phoenix Business Journal's 2014 Businessman of the Year voting behind Michael Bidwill (Arizona Cardinals), MaryAnn Guerra (BioAccel), and Bob Parsons (GoDaddy).

[11] On December 28, 2023 the Federal Trade Commission announced that it filed suit against Grand Canyon Education, Grand Canyon University, and Brian Mueller (the chief executive officer of both) for deceiving prospective doctoral students about the cost and course requirements of its doctoral programs and about being a nonprofit, while also engaging in deceptive and abusive telemarketing practices.