The 65-year-old actor gave an update Monday on Twitter after he and his wife, actress Sheila Kelley, tested positive for COVID-19.
Schiff said he is being treated at the hospital for COVID-19. Kelley is also still ill but is well enough to be home.
"Covid update. Thank you all for so much love and support. You're making it so much easier for @thesheilakelly and me," Schiff tweeted.
"I am in the hospital on Remdesivir, O2 and steroids showing some improvement every day. Sheila is home and doing better but still fairly ill. Love you all," he added.
Schiff said last week that he tested positive for COVID-19 Nov. 3 on Election Day.
"This has been the most bizarre week of our lives. @thesheilakelley is also positive. This is tough," he wrote. "We are determined to find a way to health again. We root for everyone out there who are struggling with this thing. Love from here."
Kelley confirmed Schiff's hospitalization in an Instagram post Monday, referring to him as LOML, or love of my life.
"The last 72 hours have been tough. LOML @therichardschiff is now in the hospital on oxygen and remdesivir," Kelley said. Thank you all of you for the prayers and love. We feel them. He's doing better. Getting stronger."
Kelley said the couple's son, Gus, also has COVID-19. Kelley described her experience with the virus, saying she's "never experienced anything like this" in her life.
"One minute I'm feeling pretty good and the next I'm struggling to breathe," she said. "My body is leading me through this and I am grateful to her."
Schiff and Kelley play Dr. Aaron Glassman and Debbie Wexler on the The Good Doctor, which premiered a fourth season on ABC this month. Deadline said the series remained in production after Schiff and Kelley's diagnosis and is still filming.
Schiff is also known for playing Toby Ziegler on The West Wing. He reunited with several of his former cast members, including Martin Sheen, Bradley Whitford and Allison Janney, for A West Wing Special to Benefit When We All Vote special that aired on HBO Max in October.