Hirshman and SDSU Athletics Director Jim Sterk said in a statement the school has dropped plans for the Aztecs football program to move to the Big East Conference this year and the rest of its teams to join the Big West Conference in the 2013-14 academic year.
Instead, all will stay put in the MWC, the pair said.
"After substantial discussion and consideration of a broad range of factors, San Diego State University will be continuing as a full member of the Mountain West Conference in July 2013," the said.
"We have the deepest respect for our colleagues in the Mountain West, Big East and Big West conferences who whom we have worked collaboratively during the period of conference realignment."
Under the new deal, a portion of the revenue SDSU receives from Aztec teams during the 2012-13 season will be used to pay an exit fee to the Big West Conference.
They won't, however, have to pay a similar fee to the Big East.
SDSU joined Boise State in opting this month to remain in the MWC.