The team principal and founder of the Williams Formula One team contracted pneumonia shortly after the Italian Grand Prix in September.
Williams, who was left tetraplegic following a 1986 car crash in France, contracted pneumonia shortly after the Italian Grand Prix in September.
The 74-year-old's daughter, who is Williams' deputy team principal, has missed several races to be at her father's side, but she said he was now on the mend.
"I am very pleased and happy to say he is now back home and back at the factory with us," she said.
"He came out of hospital on Monday. He contracted pneumonia after the Italian Grand Prix in Monza and he has been in hospital ever since the start of September.
"It was a slow recovery, but I am really pleased to say he is pretty much back to the old Frank we know and love, so it is lovely to have him back with us and the team."
Williams established the Williams team in the 1970s and has seen them win seven drivers' titles and nine constructors' championships.
Williams announced their line-up for the 2017 season on Thursday, with 18-year-old Canadian rookie Lance Stroll succeeding Felipe Massa as partner to Valtteri Bottas.