There's a lot of misinformation about how/when the lncome Tax started. Here's the weird truth with sauce: Lincoln signed it into law in the Revenue Act of 1862 to help fund the Civil War, but there was a big propaganda push during WWII the get regular people to pay it.

from wikipedia link to Revenue Act of 1862: Congress passed the Revenue Act of 1861 as an initial attempt to raise much-needed funds for the war. This act levied the first income tax ever levied on American citizens. The income tax placed a 3% tax on all individuals whose annual incomes were above $800 per year.[5] That would have resulted in the exemption of many citizens due to lower average income. By 1862 the United States government realized that the war would not end quickly and the revenue from the income tax would be insufficient. As a result, the Revenue Act of 1862 was passed in July 1862 before any income tax was collected under the first system. https://en.wikipedia.org/wiki/Revenue_Act_of_1862

WWII lncome Tax Propaganda featuring Donald Duck: https://www.youtube.com/watch?v=eMU-KGKK6q8