Greatly admired by Telly Monster, the Grand High Triangle Lover has appeared sporadically on Sesame Street, beginning in Season 22 in Episode 2871. The Grand High Triangle Lover is the expert on all things triangular and often officiates at triangle-related functions or contests.
He is always seen with his dim-witted assistant, Norman, who is known for loudly dinging a triangle and telling everyone to make way for his boss. Their chemistry echoes that of Ralph Kramden and Ed Norton on The Honeymooners. The Triangle Lover's square counterpart is the Grand Royal Square Lover.
In a 1994 episode, the story of how he became the Grand High Triangle Lover is told. He and Norman worked as bowling shoe renters in the kingdom of Canarsie, which had a large stone with sticks in it; whoever could pull them from the stone would become a powerful leader. The stone speaks and chooses the Grand High Triangle Lover (named Lou in that time) to be the one who will remove them. When he does, he makes a triangle with them and is appointed by the rock the position of Grand High Triangle Lover. However, Norman reveals at the end that the story is a complete fabrication and he earned his position by finding a hat with triangles on it and having everyone call him the Grand High Triangle Lover.
In his first appearance, The Triangle Lover was originally made from a Large Lavender Anything Muppet with hand-rods. After which, he was most commonly seen as a Fat Blue puppet with live-hands. Starting in Season 38, a refined design for him was used; becoming a regular Fat Blue puppet with hand-rods and a different nose.