Who is inside the Big Bird costume?

The person who has been inside the Big Bird costume the longest is Caroll Spinney. He played Big Bird for 45 years, from the very first episode of Sesame Street in 1969 until his retirement in 2018.

Since Caroll's retirement, the role of Big Bird has been taken over by Matt Vogel. He has been a puppeteer for Sesame Street since 1996 and has also operated other characters like Big Bird's best friend Snuffy.