Since this question keeps popping up in the chain burger polls, I figured I would address it in a separate post (and thus give me something to refer to every time someone asked this question): Are Carl's Jr. and Hardee's the same?
Judging from their websites, Carl's Jr. and Hardee's certainly look the same. A quick overview: They're both owned by CKE Restaurants, named after the founder of Carl's Jr., Carl N. Karcher, who opened the first Carl's Jr. in the 1950s in California. Wilber Hardee opened the first Hardee's in 1960 in Greenville, North Carolina; over 3,000 locations later, the chain was acquired by CKE in 1997. Both chains dominate different parts of the US. You can read way, way more about their histories and the merger at tesg's guide to big chain road food consumption: Hardee's and Carl's Jr (thanks, UnasBravas) .
As I grew up in a state with neither chain (New Jersey, in the house!), I have no say in whether one tastes better than the other. Tons of AHT readers have either asked or said both chains are the same, while at least two have said they're not:
it annoys me when people say hardee's and carl's are interchangable. hardee's doesn't sell anything equivalent to the "famous star," at carl's, which is their best burger.
I've lived in Carl's country and now in Hardee's country. Yes, they may be owned by the same parent co., but they are nothing alike. Carl's rocks; Hardee's blows.
So, for those who have been to Carl's Jr. and Hardee's, feel free to settle the score.