Her breakthrough role was that of Barbara in the unconventional 1968 movie Go for It, Baby (Zur Sache, Schätzchen), which captured the spirit of the times in that it presented youthful protest against the German establishment and hinted at the loosening of morals in the wake of the sexual revolution.

In the late '60s and early '70s, Glas appeared in many slapstick movies, notably in three films of the seven-part series (1967–72) Die Lümmel von der ersten Bank [de] (The Brats on the Front Bench Row).

In the 1980s and 1990s Glas concentrated on her television work, appearing in a succession of TV series tailored to her person, playing, among other characters, a veterinarian in Tierärztin Christine (1993), an energetic businesswoman in Anna Maria – Eine Frau geht ihren Weg (Anna Maria - A Woman goes her Way, 1995-1996), and the ideal teacher in Sylvia – Eine Klasse für sich (Sylvia - A Class of her own, 1998-2000).

Glas was married to the film producer Bernd Tewaag [de] from 1981 until their divorce in 2003; they had three children.

She is now the step-mother to Sophie Hermann, a social media influencer and fashion designer who appears in the UK reality TV series Made in Chelsea.