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Apple Jacks is a brand of cereal produced by Kellogg's and targeted mainly at children. It was introduced to the U.S. as "Apple O's" in 1965 after being invented by William Thilly who is currently a professor at MIT. In 1971 the name "Apple Jacks" was put into action by advertisers. The product is described by Kellogg's as a "crunchy, sweetened multi-grain cereal with apple and cinnamon." Apple Jacks is one of the top four cereal brands marketed within stores and is most heavily marketed on Kellog's internet platform. 
Originally, the Apple Jacks were only orange and O-shaped, until 1998 when the green O-shapes were added to the cereals. In a marketing promotion in December 2003, Kellog manufactured blue carrot shapes instead of the green O shapes. More recently, Apple Jacks has introduced New Apple Jacks 'Crashers' – a unique cereal piece that replicates a mid-2007 advertising execution when mascots Bad Apple and CinnaMon were accidentally fused together. The latest (limited) edition, in 2010, are Apple Clones, with red pieces shaped like apples. In 2012, Apple Jacks was brought to Canada in a Limited Edition box.
The first Apple Jacks mascot in the 1960s was "Apple Guy", a figure made from cutting a face onto an apple and applying a hat and pieces of cereal for eyes.
In the late 1960s the box depicted an "Apple Car" with pieces of cereal for wheels.
Around 1971, the official mascots became "The Apple Jacks Kids", a simplistically drawn animated boy and girl duo. The commercials featured the children singing and tumbling around. Their reign lasted for twenty-one years, making them the most well-known Apple Jacks mascots and most universally associated with the cereal in the public's memory. During this time, the Apple Jacks jingle became an integral part of the ad campaign: "A is for apple, J is for Jacks, Cinnamon-toasty Apple Jacks!" This campaign was retired in 1992.
Starting in 1992, there was an advertising campaign that featured children expressing their enjoyment of Apple Jacks, regardless of its lack of apple flavor. The slogan for this campaign became "We eat what we like". The shift toward marketing cereals directly at children signaled the growing recognition of children's influence on family purchases. The commercials took place in such normal kid hang-outs as the at school, garage, ballet class, the kitchen and such. In each commercial, a group of children are having Apple Jacks, when suddenly, some other people, such as adults or jealous kids, bash the group. The group then explains their love of the cereal, and at the end of the commercial, would pose for a group Polaroid.
As of 2004, the marketing mascots are a care-free Jamaican cinnamon stick named CinnaMon and an accident-prone apple named Bad Apple. Labeled as Apple Jacks Adventures in print advertising, the commercials focus on CinnaMon upstaging Bad Apple by reaching a bowl of Apple Jacks before he can, in spite of the apple's attempts to stop him. Bad Apple's antagonistic nature was latter dropped; Apple and CinnaMon were then portrayed as highly competitive friends, both getting into the bowl. The campaign was slated to be retired in 2007, and replaced by a retread of the 1990s campaign focused on children, but fan response to Apple and CinnaMon helped them remain as the mascots. In 2007, Apple and Cinnamon were fused together with Cinnamon sticking through the center of Apple with both of their legs at the bottom of their body. They remained this way for a few of the commercials until they became unstuck by a special machine.
According to the label on the box, in 2010, each 28 gram serving had 100 calories, three grams of dietary fiber, and 12 grams of sugar. The front of the box indicated that the inclusion of fiber was a change from previous versions of the cereal. Apple Jack's packaging contains child features and had no health ingredient claims until 2009, when they were reformulated to contain fiber.
In 2013, Kellogg's Apple Jacks introduced a new multi-grain cereal called "Cinnamon Jacks," with CinnaMon as its sole mascot.