Robert Simmons or commonly known as Mr. Simmons is a character in the Hey Arnold Show as Arnold's second and fourth grade teacher. In the Kid Crusaders stories he is Cartoon Town Elementary School's Algebra teacher. He is voiced by Dan Butler.
Mr. Simmons is Arnold's (second) fourth grade teacher, who took over from Miss Slovak in the episode "New Teacher". He demonstrates a love for teaching immediately, forming the desks into a circle to encourage stronger interaction between students. He also encourages learning by teaching the students to always ask "why?". The students do not like Mr. Simmons' teaching style at first and plot a plan to break him down and to cause him to quit. After a series of pranks (which even Arnold participates in) Harold finally breaks his spirit by eating his lunch. Mr. Simmons quits teaching that afternoon.
The next day, the class expects a new teacher that they can break down. Mr. Wartz announces that he has a solution to the classes behavior problem. The solution is U.S. Army drill sergeant, Lieutenant Major Goose, a strict, child-hating taskmaster. The class soon realizes that class with Mr. Simmons wasn't as bad as they thought it was after experiencing Mr. Goose's tyranny. The class breaks Goose down the same way they did Simmons and make peace with Mr. Simmons by making a creative circle and inviting him in, making him rethink his resignation. Mr. Simmons remains their teacher for the remainder of the show.
In the episode "Arnold's Thanksgiving", it's revealed that Mr Simmons' first name is Robert during the Thanksgiving play where a family scene that included characters whose names matched his own Thanksgiving guests. His other Thanksgiving guests, or rather those whom he is thankful for, are his mother Pearl, his friends Peter and Joy, and his Uncle Chuck.
He was also briefly made principal in "Principal Simmons", though his lax methods such as his kindness, when not backed up by Wartz' discipline, fall flat and create chaos. Wartz himself has a change of heart, becoming much kinder.
In the episode, "A Day In The Life Of A Classroom", Mr. Simmons was named Teacher of the Year.
In one of the chats, Craig Bartlett stated that Mr. Simmons is gay though this was never disclosed during the show. However, it is hinted that he is in a secret relationship with Peter in "Arnold's Thanksgiving."
- Though it's unknown when he'll make his first appearance. He is the Kid Crusaders Algebra Teacher.