The 28-year-old USA international penned a four-year extension at Villa Park on Saturday.
"Brad has been exceptional for the club, really fantastic on and off the pitch," Lambert told Villa's official website.
"He's always bubbly around the place and a really solid character. He's a good guy as well which is really important. Overall, he's a credit to the club."
Guzan's new terms are due to expire in summer 2017.