Lamely, making his 10th Nationwide start, closed with a 6-under 65 in windy conditions on Ohio State Universitys Scarlet Course to match Fowler at 11-under 273.
Fowler, attempting to join 2007 champion Daniel Summerhays as the only amateur winners in tour history, shot a 68, bogeying the final hole of regulation.
The 29-year-old Lamely earned $139,500 to jump from 135th to 12th on the money list with $154,826. The top 25 at the end of the season will earn 2010 PGA Tour cards.
My goal is still the same, Lamely said. The goal still is to get on the big tour. Its the same goal Ive had forever. I just helped myself significantly today.
Tom Gillis (71), third-round leader Dave Schultz (77) and Gavin Coles (74) tied for third, four strokes back at 7 under.
Lamely and Fowler both parred the first playoff hole, the par-4 18th.
On the 164-yard 13th on the second extra hole, Fowlers tee shot found a front bunker, while Lamely missed long and left in the heavy rough. The winners delicate downhill wedge from a gnarly lie stopped 3 feet from the cup.
A year ago I might not have even gotten that one on the green, Lamely said. I might have gotten it on the green, but it definitely wouldnt have been 3 feet.
Fowler blasted his second shot 12 feet past the hole and his par attempt slid over the right corner of the cup. Lamely then tapped in for the win.
I hit some really good putts there at the end and they just didnt go in, Fowler said. I was giving myself good looks all day. I struggled a little bit coming in and thought I hit some good shots there on 18.
Lamely was eight strokes behind Schultz when play began Sunday.
Obviously, I needed some help, starting as far back as I did, said Lamely, who grew up playing in windy conditions in Lake Conroe, Texas.
The best part of the day was when we got to the course. The wind was already blowing so I thought I had a chance. I knew I had to go out and play well obviously. I went out and hit a lot of really good golf shots. I drove it better today than I have all week and I took advantage of that.
Oklahoma States Morgan Hoffman, the winner of the Phil Mickelson Award as the top Division I player, closed with a 70 to tie for eighth at 5 under.