The firefighter, who was not identified, slipped in rugged terrain while he was helping to put out a flare-up. He was taken to a hospital where he was in stable condition and expected to make a full recovery.
"It's steep country, it hasn't burned in a long time. You get a little bit of water on the hillside and it gets slick," said Cal Fire Division Chief Tony Mecham.
Officials said the wildfire had burned 28,000 acres and was 56 percent contained Saturday.
All mandatory evacuations that were ordered for the Sycamore Canyon, Deer Creek, Yerba Buena, Broome, La Jolla, Leo Carrillo, Cotharin Road areas have since been lifted.
The weather will likely continue to help the firefight through the weekend as temperatures drop up to 20 degrees.
"Now we're looking at cooler temperatures, much higher humidity. We're now getting the coastal influence now off of the ocean like we normally get here, so that's going to make things a lot better for the crews out here on the fire," said Ventura County Fire Department Cpt. Dan Horton.
Controlled burns were executed overnight as crews fought fire with fire, burning back into the blaze to get rid of surrounding fuel and snuffing out the flames.
Fire officials warn that the fire is not entirely out and residents to take precautions.
"We still have smoke," said Horton. "Anybody that's in the area, we just recommend that you stay in your house, try to limit your time outdoors, close your windows, and things like that."
So far, no homes have been destroyed.
Janet Rothman and her 12-year-old daughter Michelle couldn't wait to get home. Their family was forced out of their Dos Vientos home when the fire broke out Thursday morning.
"It's a big relief," Rothman said. "We've wanted to get home, so just getting back to normal will be a good thing, you know, sleeping in your own bed and not having to worry."
Fueled by strong winds, hot temperatures, and low humidity, the wind-whipped fire has threatened 4,000 homes. Fifteen homes suffered some damage, but none have been destroyed. At least 25 outbuildings and other property were destroyed.
"It was scary, the whole sky was like orange," Rothman's daughter said. "It was so weird just seeing everybody go."
Full containment isn't expected until Monday.