Calvin and Hobbes was first conceived when Watterson, having worked in an advertising job he detested, began devoting his spare time to cartooning, his true love. He explored various strip ideas but all were rejected by the syndicates to which he sent them. However, he did receive a positive response on one strip, which featured a side character (the main character's little brother) who had a stuffed tiger. Told that these characters were the strongest, Watterson began a new strip centered on them. The syndicate (United Features Syndicate) which gave him this advice rejected the new strip, and Watterson endured a few more rejections before Universal Press Syndicate decided to take it.
The first strip was published on November 18, 1985 and the series quickly became a hit. Within a year of syndication, the strip was published in roughly 250 newspapers. By April 1, 1987, only sixteen months after the strip began, Watterson and his work were featured in an article by the Los Angeles Times, one of America's major newspapers. Calvin and Hobbes twice earned Watterson the Reuben Award from the National Cartoonists Society, in the Outstanding Cartoonist of the Year category, first in 1986 and again in 1988. He was nominated again in 1992. The Society awarded him the Humor Comic Strip Award for 1988.
Before long, the strip was in wide circulation outside the United States; for more information on publication in various countries and languages, see Calvin and Hobbes in translation.
Watterson took two extended breaks from writing new strips — from May 1991 to February 1992, and from April through December of 1994.
In 1995, Watterson sent a letter via his syndicate to all editors whose newspapers carried his strip. It contained the following:
The 3,160th and final strip ran on Sunday, December 31, 1995. It depicted Calvin and Hobbes outside in freshly-fallen snow, reveling in the wonder and excitement of the winter scene. "It's a magical world, Hobbes ol' buddy!" The last panel shows Calvin and Hobbes zooming off on their sled as Calvin exclaims: "Let's go exploring!"
Source : Wikipedia