It was seventh-seeded Querrey's third title of the year and all have been achieved on different surfaces _ he won in Memphis on hardcourt and in Belgrade on clay.
The match was the first all-American final at Queen's since Todd Martin defeated Pete Sampras in 1994. Querrey is the eighth American winner of the pre-Wimbledon tournament.
Fish had three break points to go 2-0 ahead in the first set. But Querrey held him off with aces on the first two points and Fish netted a backhand on the third.
Games then went easily with serve, although Querrey was stretched to deuce at 6-5 before taking the set to a tiebreaker.
After winning four consecutive points from 3-3 to take the tiebreaker, Querrey then began the second set with four aces to hold the opening game in just 38 seconds.
Fish continued to pressure his opponent, and he was rewarded with a break for 3-2 when Querrey ended a long rally by hitting a forehand long.
Fish failed to serve out the set at 5-4, allowing Querrey to level after a backhand error. Fish was broken again for the match when he mis-hit a volley on Querrey's second match point.