Harris English took the outright lead after a beautiful tee-shot on the 16th to land within seven feet of the hole, which he sunk for birdie.
He immediately gave the shot back on the 17th, but another birdie on the 18th from just under 30ft gave him back the lead.
Only Hickock could catch him, and he did so with a birdie from 9ft, taking the tournament to a playoff for the first time since 2017.
What happened to Bubba?
Bubba Watson had played exceptional golf all week, and looked set to win the Travelers for a fourth time before it all went wrong for the 42-year-old.
Bubba was standing pretty at the top along with a few others at 13-under-par, and looking comfortable, albeit wasteful.
In the first 13 holes, he had hit 11 greens-in-regulation and had 12 putts – one from the fringe – for birdie, converting three of them.
He had played the final five holes in one-under-par in the previous three rounds, and a similar score would have been good enough.
Unfortunately for Bubba fans, he bogeyed the 14th, 15th, 16th and 18th, and doubled the 17th to drop six shots.
Harris English, 31, and Kramer Hickock, 29, went to the 18th for what was going to be the second longest playoff in PGA history – 11 holes at the 1949 Motor City Open.
Kramer almost won with a 42ft putt on the second playoff hole, but the ball rode the ledge and stayed out to the dismay of the player, his family and the fans.
On the 17th (fifth playoff hole), he had a 10-footer for victory, and it flirted with the ledge again, without going in.
On we go…
One hole later, English made par, leaving Hicock with a tough scramble to save par. The putt, from around 12ft went in.
After a couple more pars on the 17th, we went back to the 18th for the eighth playoff hole. This time English had a mid-range birdie putt for victory, which he made no mistake with.
The victory was Harris English’s fourth on the PGA tour, while Kramer Hickock will need to wait a little longer to break his duck.