He handled business in the Saiyan battle. Dude caught more Saibamen bodies than Piccolo and Tien combined, and came the closest to killing Nappa out of everyone. It was all downhill for him after the Namek Saga ended though. At least he got to wife the coldest woman in the series to make up for it.
I'd say that Piccolo did more work, but I consider him to be a starter more than anything. Out of the humans, I'd say that Krillin did the most work. Most underrated member of the squad, hands-down. Tien is dope for standing up to cell, but he's spent too much of the series on King Kai's planet in the bushes or offscreen on that
with Chaiotzu to be considered the GOAT human IMO.