He will face a rejuvenated 10th seed David Nalbandian in the final on Sunday after the 2002 Wimbledon finalist completed a stylish 6-4 6-4 win over 21-year-old Bulgarian Grigor Dimitrov later in the day.
Cilic and Nalbandian have recent history after Cilic completed a 5-7 6-4 4-6 7-6 (7-2) 6-3 win in five hours over the wily baseliner in Croatia's Davis Cup tie against Argentina in Buenos Aires two months ago. It will be their first meeting on grass with Nalbandian holding a 4-1 lead from their five previous encounters.
Cilic had to survive nine break points on his way to winning the first set against the big serving Querrey, who won this tournament two years ago.
Querrey came up with two breaks of serve in claiming the second set, but Croatian Cilic held himself together well in the third set as Querrey threw in a double fault and missed a drop shot on his way to dropping serve in the eighth game of the third set.
Cilic remained composed in some awful wind to convert a winning volley on his first match point to finish off matters.
"It was really windy, especially when you toss the ball as high as me and Sam," said world number 25 Cilic, who has been as high as nine in the world.
"I found it tough to control my serve, it was not easy..you just try to do the best you can and take the opportunities you have.
"It would mean a lot to win the title, especially before Wimbledon. I've played here a lot and it feels really good to make final."
There were five breaks of serve in the first set of Nalbandian's match with Dimitrov, but the Argentine made the decisive thrust by breaking at 3-3 before seeing out the set with his deft touches and experience too much for his opponent.
Dimitrov rallied briefly in the second by winning three straight games to lead 4-3 having trailed 3-1. Nalbandian was clearly cross with himself, but broke for a second time in the set after Dimitrov missed an overhead in the wind holding advantage at 4-4.
Nalbandian engineered a brilliant point to enforce the break seconds later as he drew Dimitrov to the net with a drop shot before converting the volley. He held serve with minimal fuss to finish off the match in straight sets.
"The wind made it very tough and I don't think it was a good match. We both made a lot of mistakes," said Nalbandian.
"This week hasn't been easy..a lot of rain, delayed matches. You have to be fit to play at this level, I'm here fighting all the time."