The 25-year old Ram, a lucky loser after top-seeded Mardy Fish withdrew on Monday to replace Andy Roddick on the United States Davis Cup team, won the first all-American final on Newport's grass courts in seven years. It was his first ATP final.
It was the first ATP final for Ram, the 181st ranked player entering the week, and the lowest ranked to win an event this year.
"These days don't come around very often unless you're [Roger] Federer or [Rafael] Nadal. There's definitely pressure," Ram said. "I tried to play tennis instead of thinking about what the moment was."
Ram withdrew from his qualifier match on Monday, knowing he'd be placed in the draw when Fish pulled out.
"Winning tournaments is not normal on the tour for 99 percent of us," he said.
The 21-year old Querrey played in his third final and was seeking his second title. His only tour championship came in Las Vegas last year.
After losing the first set in a tiebreaker, Ram decided to change his approach against the hard-serving Querrey late in the second set. With Querrey struggling on his first serves, Ram attacked the net against the second.
At 30-40 in the 12th game of the second set, Ram broke and sent the match to third set with a lunging backhand from close.
In the final set, Ram broke in the eighth game, winning with a well-placed forehand cross to go up 5-3. He raised both arms into the air after Querrey hit a forehand long on the match's final point.
"I wasn't serving as well as I was the previous four matches," Querrey said. "Part of it was due to him. I didn't quite have the sync I did the last two days."
Querrey, who had 80 aces this week, still had a reason to smile when it was over. His first-serve percentage was 56; compared to 70 on Saturday.
"I'm going to the Home Run Derby and All-Star Game," he said. "I'm not too bummed."
Ram earned $79,000 for his singles title. Querrey, who was very excited when he was able to secure the baseball tickets earlier this week, collected $41,500.
Taylor Dent beat James Blake in Newport's last all-American final.