Gates had 389 yards as a rookie, which was a decent total, but in 2004 he became a much bigger part of the Chargers' offense, earning three straight First Team All-Pro Selections and eight consecutive Pro Bowls.  From 2004 to 2014, he would have at least 700 Receiving Yards with two 1,000 Yard years. For years, Gates was a money-man, punching the ball into the end zone 116 times for the Chargers, with eight 8-plus TD seasons.

Gates was released before the 2018 season, but he was resigned for one more year following an injury to Hunter Henry. After a year as a Free Agent, he retired in January of 2020.

At the time of his retirement, he is the all-time leader in Touchdowns for a Tight End, and he is currently the franchise leader if Receiving Yards (11,841) and Receiving Touchdowns (116).