According to drinks historian David Wondrich, the drink is probably derived from the gin punches that gained popularity during the early 19th century. A common story is that an enterprising barkeep who worked for Limmer’s Hotel in Lodon, John Collins, named the concoction after himself. However, it’s arguable whether Collins actually invented the combination of ingredients, or just helped to bring it to the masses.

The Tom Collins was immortalized in Harry Johnson’s 1882 book, New and Improved Bartender’s Manual: Or How to Mix Drinks of the Present Style, but has been featured in countless iconic bartending manuals since. It has remained popular for over a century, and helped create the template for other sour-sparkling beverages like the French 75 and many modern spritzes.

Reference: https://www.liquor.com/recipes/tom-collins-2/