Recently a wine-buff friend of mine poured a glass of pricey Bordeaux for me. “How about that aroma?” he asked. I had to confess to him that my sense of smell has deteriorated a lot. “I usually smell good, but I don’t smell well,” I quipped.

Few pairs of words get more groans from us grammar hair-dividers than “well” and “good.” Above, “good” describes me, while “well” describes my olfactory prowess. Each word can be either a noun or an interjection without any confusion; “well” can also be either an adjective or an adverb, while “good” can serve as an adjective.
And this is where the debate starts.

Ask someone, “How are ya?” and most people will say, “I’m good.” However, some grammar wonks will sniff and respond with a superior air, “Oh, I’m well, thank you!”
It turns out either reply is okay. That’s because forms of the verb “to be” (and some other verbs) are known as linking, helping or copular verbs. These are frequently — but not always — followed by adjectives that describe the subject of the sentence. In the example above, both “good” and “well” function as adjectives.
(Arguably, if someone is asking specifically about your health, “well” is probably the better reply — especially if you have been … unwell. But it would also be correct to answer, “I’m good.” And your friend could reply equally correctly, “You’re looking good!”)
The same applies if your friend is from someplace like New Jersey, Philadelphia or Brooklyn, and they ask, “Howya doin’?” Answer “I’m doin’ good,” and those eagle-eyed grammarians will insist that “good” isn’t an adverb, so you’ve just implied that you are performing good deeds. Turns out that “to do” can serve as a linking verb, so your original answer is correct — “good” is an adjective here.
The grammarians can keep saying, “I’m doin’ well,” without being incorrect. But they sure will sound funny out in Brooklyn Heights. KnowhatImean?