"I feel great," the 58-year-old actress told E! News on Sunday night on the red carpet. "When you do Broadway, you have a family there and one at home as well. I had so much love through the process. I'm very thankful."
She later added that she is no longer in treatment and had "won" her cancer battle.
Wilson, who is married to Oscar winner Tom Hanks, revealed in April that she had been diagnosed with breast cancer and had undergone a double mastectomy.
"I have taken a leave from the play 'Fish in the Dark' to deal with a personal health issue," the "Girls" actress told People magazine. "Last week, with my husband by my side, and with the love and support of family and friends, I underwent a bilateral mastectomy and reconstruction for breast cancer after a diagnosis of invasive lobular carcinoma."
She added that she expected to make a full recovery because doctors caught the cancer early.
About a month after her surgery, the actress resumed her role on stage in "Fish in the Dark," opposite Larry David.
Colin Hanks, Tom Hanks' son by his late first wife Samantha Lewes, accompanied Wilson to the Tonys.
Wilson tweeted a photo from inside Radio City Music Hall.
Colin also posted a photo of the two of them on the red carpet.