He won gold in the 50-meter freestyle earlier in the day.
The U.S. men finished in 3:26.78, beating the previous world record by .50 seconds.
Great Britain took the silver, finishing .73 behind the Americans. Italy took bronze.
The relay opened with Ryan Murphy on backstroke, followed by Michael Andrew, who finished his breaststroke leg with the Americans in second behind Great Britain. Dressel then regained the lead and Zach Apple closed it out, anchoring the freestyle leg.