* Early Life: He grew up in Montana and developed a love for drawing from a young age. However, he initially went to college for engineering and even served in the Navy during World War II.
* Post-War Career: After the war, he worked in advertising for a while, which exposed him to the world of commercial illustration.
* Early Comic Strips: He finally began submitting cartoon strips in the late 1940s, but initially, they weren't successful. He even worked on a few short-lived strips before hitting it big with Dennis the Menace.
* Breakthrough with Dennis the Menace: Ketcham's "Dennis the Menace" strip debuted in 1951. This was a huge hit and catapulted him to fame. The strip was syndicated across the world, and he continued to draw it until his death in 2001.
So, while he may not have been a cartoonist from the very start, his early experiences in advertising, engineering, and the Navy shaped his creative thinking. This eventually led to his iconic creation, Dennis the Menace, solidifying his place in comic strip history.