Who was the first US president to file an income tax report ?

Lincoln?

Since the first US Income tax laws were passed in 1861, I assume that Lincon followed the laws and filed.

DG - that why i guessed lincoln also.

hmmmm, I found another 'first Chief Executive'.

hmm ... i found a site that says Harding - March 14th 1923. (many sites actually, but they are all papers who seem to get their "this day in history" off the same service)
seems odd that Lincoln and those between Lincoln and Harding didn't though.