Doing the math from the article above, he must have been around 24 years old when “Don’t You Just Know It” was released.
Yeah, he was a contemporary of Fats Domino, they were both young guys in the New Orleans R&B scene when it started to transition to Rock ‘n Roll, so they were able to take advantage of that trend.
One little known fact is that sometimes when you hear a Fats Domino record it’s actually Huey Smith playing the piano part. Even though Fats could play, he knew Huey could do the simple arrangements on the record just as well as he could, so he would sometimes just have him record the piano part so he could focus on the vocals. Then later on, in the 60s, another New Orleans piano player, James Booker, would get gigs to be “Huey Smith” for live shows when Huey couldn’t make it. Everyone knew Huey’s records but unlike Fats, they didn’t usually know what he looked like, so if he didn’t want to bother doing a gig, he would toss that work to Booker.