He is best remembered for his performance in a Thanksgiving Day game in 1974 against the Washington Redskins. Longley, then a rookie, came into the game for an injured Roger Staubach with the Cowboys trailing 16-3 in the third quarter, and facing elimination from the playoffs. After hitting Billy Joe Dupree for a 35-yard touchdown pass, he led the Cowboys on a 70-yard drive capped by a 1-yard Walt Garrison touchdown run. Finally, with the Cowboys behind 23-17 and with only 28 seconds left with no time outs, Longley hit Drew Pearson at the left sideline for a 50-yard hail mary pass touchdown which gave the Cowboys a dramatic 24-23 come from behind victory.