Redmayne stars in the film as Tom Hayden, one of the 7 defendants charged with conspiracy and inciting to riot for their role in protests during the 1968 Democratic National Convention.
"It sort of plays to all of Aaron Sorkin's genius, you know," he continued, before describing what it was like to work with the filmmaker.
"The amazing thing about doing Sorkin is he's just so much brighter than you are and his characters are so much brighter than you are that you get, momentarily, to have this sort of speed of thought and feel slightly more intelligent," Redmayne said.
The Trial of the Chicago 7 is in select theaters and is coming to Netflix on Oct. 16.
Redmayne also discussed how the third Fantastic Beasts film is back in production and how his home became what he described as an animal sanctuary during the COVID-19 pandemic.
The 38-year-old said he took care of five chickens and built them a chicken hutch.
"I spent most of lockdown running into other people's gardens trying to sort of retrieve chickens that were causing havoc," Redmayne said.