in one's glory

At one's best, happiest, or most gratified. For example, She was in her glory playing her first big solo, or In the classroom, this teacher's in his glory. [c. 1800] Also see in one's element.

The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.