Reed arrived in New York occupying eighth position on the points list for the biennial match against Europe and booked his place with victory at Bethpage Black, jumping to fourth in the standings.
Rickie Fowler did not fare as well. He needed to finish third or better to secure his position after starting the tournament 12th on the list but slumped over the closing stages, dropping three shots in the last four holes to finish joint seventh.
Fowler's loss was Zach Johnson's gain as the 2015 British Open champion claimed the eighth and final automatic spot.
Two-times Masters winner Bubba Watson finished ninth on the list, while Fowler came in 11th, behind J.B. Holmes.
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Watson and Fowler will be among those hoping to be included as one of four wildcard picks next month when captain Davis Love completes his 12-man team for the three-day event at Hazeltine, Minnesota that starts on Sept. 30.
Europe have won three Cups in a row, and eight of the last 10.
"I want sweet revenge, just like our whole team does," said Reed, who has represented the United States in the Ryder Cup in Scotland, the Presidents Cup in South Korea and at the Olympic Games in Brazil.
"So now, I finally get to play for the United States in the United States and I cannot wait to see how the fans are, and just have the whole crowd on our side this time," added the 26-year-old.
Love will choose three of his wildcards after the BMW Championship on Sept. 11 and make his final selection two weeks later after the Tour Championship, only five days before the Ryder Cup starts.
A change in selection policy was made to ensure a player on a hot streak does not miss out on the team. Two years ago Billy Horschel won the BMW Championship and the Tour Championship but missed the Ryder Cup as the team had already been finalised.
Five of the eight automatic qualifiers this time also played on the losing 2014 team -- Jordan Spieth, Phil Mickelson, Jimmy Walker, Reed and Johnson.
"It's going to be so much fun. I know we're going to work so hard to keep that Cup back home," said Reed.
AUTOMATIC QUALIFIERS:
Dustin Johnson
Jordan Spieth
Phil Mickelson
Patrick Reed
Jimmy Walker
Brooks Koepka
Brandt Snedeker
Zach Johnson
(Reporting by Andrew Both; Editing by Tony Jimenez/Peter Rutherford)
