Claiming the 72nd pole position of his career and the 11th of the season, Hamilton has to score 16 points more than Vettel to wrap up the title in Austin.
If Hamilton wins and Vettel finishes outside the top five, he will be champion while he will also be crowned champion if he is second and Vettel is outside the top eight.
If Hamilton finishes third or lower, the 2017 title battle continues to the remaining races in Mexico, Brazil and Abu Dhabi.
Hamilton’s Mercedes team-mate Valtteri Bottas qualified third ahead of Red Bull Racing’s Daniel Ricciardo and Ferrari’s Kimi Raikkonen.
The other Red Bull racing driver Max Verstappen qualified sixth but will start, from the back of the grid after being given a 15-place penalty for taking new power unit parts.
Frenchman Esteban Ocon qualified seventh for Force India ahead of Carlos Sainz, who is making his debut with Renault after moving from Toro Rosso.
Two-time champion Fernando Alonso of McLaren was ninth ahead of Mexican Sergio Perez in the second Force India.