Johnson finished the tournament with a four-round aggregate 261, 19 under par.
Johnson has been dominant in multiple aspects of his game this season.
"It feels like it's been a long time (since my last win), even though it's only been six months". Putnam's solitary birdie of the round came two holes later to narrow the gap to two shots, but he wouldn't come any closer than that for the remainder of the round.
Cook's 5 under on Sunday tied him with Phil Mickelson and Tim Herron for the best scores of the final round and moved him up the leaderboard into a tie for sixth.
Johnson, 33, lost top spot in the world rankings to compatriot Justin Thomas, who is not taking part in the tournament.
Neymar and Coutinho egged by Brazil team-mates
The Selecao superstar moved to 55 goals in 85 caps, equaling the record of 1994 World Cup victor Romario. However, he was a different player in Vienna and managed to score his 10th goal in 17 games for Brazil .
No player has followed success the week before the US Open with victory in the second men's major of the year, although Johnson is confident of breaking that record and winning the event for a second time. Instead, he rolled in the putt to keep his lead, and birdied the 13th to increase it to three. "I hit a lot of good shots and had a lot of good looks at birdies".
Johnson had already shown off his ludicrous velocity earlier in the day by hitting a 307-yard drive with an iron on the hard par-4 10th hole.
"I'm rolling it down the line I'm looking", Johnson said.
"I really like this golf course because you have to focus on every shot". He holed out from the right front bunker for birdie on the par-5 No. 16.
Blaum redeemed a bogey at the first with seven birdies in a 64 and Putnam matched that effort as both seek a first win on the PGA Tour.
Justify wins Belmont Stakes to become 13th Triple Crown champ
It had previously won the Kentucky Derby and the Preakness Stakes , which together make up horse racing's most sought-after title. Bob Baffert and Mike Smith have teamed up to win a big race at Belmont Park . "I told him I loved him", he said.
"It obviously went pretty well", said Snedeker, the 2012 FedExCup champ.
Putnam, a two-time victor on the Web.com Tour, had only one bogey through his first three rounds.
Dustin Johnson is back as world No 1going into this week's US Open after reclaiming the mantle with an emphatic victory in Memphis on Sunday night.
Mickelson headed a group of six golfers finishing in 12th at 6 under. And from that moment on, Johnson's second title of 2018 was never in doubt.
Watch the Square Enix E3 2018 press conference live stream right here
Sadly, both also had immaterial showings with next to no details revealed about what they will be like; the ultimate E3 tease. The most surprising news of the short presentation was a meeting of two of the most popular franchises in gaming.