Rooney was granted a temporary restraining order against his stepson, Chris Aber, this week, The Hollywood Reporter said. The entertainment industry newspaper did not say who the conservator is.
The actor accused Aber of denying him medication and food, controlling his finances and verbally abusing him.
A hearing in the matter is scheduled for Feb. 24.
"All I want to do is live a peaceful life, to regain my life and be happy. I pray to God each day to protect us, help us endure, and guide those other senior citizens who are also suffering," Rooney said in a statement issued to The Hollywood Reporter.
Rooney's film credits include "Boys Town," "Babes in Arms," the Andy Hardy film series, "Breakfast at Tiffany's" and "Night at the Museum."
He received a special Academy Award in 1938 and an honorary award in 1982, and was nominated for five acting Oscars.
A five-time Emmy nominee, Rooney won an Emmy in 1982 for his performance in "Bill," as a mentally challenged man making his way into the world for the first time.