The decision was unanimous, which means the state's contribution will stay the same when it comes to paying a new president, but private donations can supplement the salary by up to 10 percent.
The full board will vote on the amended policy on Wednesday.
"The salary for the new president would remain the same level as the salary from the old president, but we would be looking to potentially pay a supplement through private funding, and those funds would be generated specifically for this," said CSU spokesman Mike Uhlenkamp.
The California Faculty Association (CFA) and CSU are currently negotiating a new contract, and the union has authorized a strike. Talks broke down over the weekend.
"When student fees have gone up astronomically, and the contract negotiations haven't even resulted in our being paid what was promised in the last contract, well, it shows where the priorities are," said Cal State professor Steve Fleck.
CFA represents 24,000 professors and other staff members who have not received a pay raise in years. The trustees voted in March to give the 10-percent raise to the presidents of CSU Fullerton and CSU East Bay.
The university system said it needs to pay qualified people more money in order to attract and keep them, but the union said this is simply the board playing a shell game. Faculty members said a better use of private donations would be to support academic programs, not new presidents' salaries.
The 23-campus system has lost $970 million in state funding in the last four years, forcing it to raise tuition, cut enrollment and lay off employees.