She has been doing this a LONG time. Read her bio at Wikipedia.
Back ... way back, in the day when I was sewing costumes in some of the New York shops, it seemed like she designed every other show. Take a look a just her Broadway credits on this website.
But, she designs so many other places, too, here and in England, everything from straight plays, to opera, ballet, and TV. She has been nominated 18 times for a Tony award, never won, but then received a lifetime achievement award in 2014.
And, she is STILL at it. In this video below she talks about her designing process and research for the play she is costuming right now, Therese Raquin, on Broadway.
I found this SO amazing to listen to. I thought you costuming people would be like it, too, no matter what kind of costuming interests you. A lot of thought goes into any costume and this is how Jane Greenwood thinks.