1966: The Chiefs make another big improvement through the draft signing RB Mike Garrett even though he was also drafted by his hometown Los Angeles Rams. After starting the season 3-0 on the road, a crowd of 43,885, the largest ever to witness a sports event in Kansas City, turned out for the home opener against the defending AFL champion Buffalo Bills, the home opener against the defending AFL champion Buffalo Bills. The Chiefs dropped a 29-14 decision to the Bills, but, after the contest, Chiefs coach Hank Stram and Buffalo head coach Joe Collier negotiated a trade in the middle of the field. Kansas City got kicker Mike Mercer for a fifth-round pick, solidifying one of the few weaknesses on the squad. The Chiefs would go on to finish with an 11-2-1 record, winning the Western Division by 3 games to set up rematch with Bills in Buffalo in the AFL Championship Game. Using a dazzling I-formation offense and a smothering defense, the Chiefs dominated the Bills in Buffalo, 31-7, on New Year's Day to win the franchise's second AFL crown and earned a place in the first AFL-NFL World Championship Game.

Super Bowl I: Lamar Hunt who was the driving force behind the formation of AFL won a major victory when the NFL and AFL agreed to play a World Championship game after the season. So it was only appropriate that his Chiefs were the AFL's reprehensive in the first of these games billed as the AFL-NFL Championship Game.  Initially the game did not get much attention as everyone assumed that the Chiefs were no-match for the powerful Green Bay Packers who won the NFL Championship. The game was not even sold out as the Los Angeles Coliseum only was filled to 2/3 of capacity. The Chiefs would manage to stay close for a half only trailing 14-10 at halftime, but the Packers would turn on the after burners scoring 21 unanswered points in the 2nd half for the 35-10 victory. However, the game would be the beginning of a tradition and within a few years would become the premier sporting event in America. The game would eventually be called the "Super Bowl", a name that Lamar Hunt himself came up with after seeing his daughter playing with a Super Ball

1969: Ten years after Lamar Hunt helped create the AFL the league which no one thought would last, was playing its final season. However, the league, which no one took seriously when it was first formed, was not folding instead it was becoming part of the NFL following the 1969 season. Three years after a merger to form a common draft and the Super Bowl III AFL finally had the legitimacy it sought for years when the New York Jets stunned the Baltimore Colts, This set the stage for the NFL to take over the AFL, keeping the league intact, while adding 3 NFL teams so both the newly billed AFC, and NFC would have 13 teams apiece. Although the move ended the AFL as a separate league it would only make pro-football stronger, and would prove to be a victory for Lamar Hunt and the misfit AFL owners, who would now be on equal footing with the NFL owners, and teams. The Chiefs opened the final AFL season with impressive wins over San Diego and Boston, but lost QB Len Dawson with a knee injury. The next week, backup Jacky Lee went down with a broken ankle, leaving the team's most crucial position in the hands of two-year pro Mike Livingston. In his first game Livingston struggled in a loss to the Cincinnati Bengals. However Livingston would bounce back and the Chiefs would win their next 7 before losing at home to their nemeses the Oakland Raiders. As the season was winding down Len Dawson returned, but after the Chiefs lost to the Raiders again the Chiefs were forced to settle for 2nd place with an 11-3 record. However, the AFL in its final year gave a playoff spot to their division runner-ups so they could get an extra round of playoffs. In the 1st Round of the Playoffs the Chiefs were matched up with the defending Super Bowl Champion Jets in New York. The Chiefs defense would dominate all game shutting down Joe Namath, and holding the Jets to 6 points as the Chiefs advanced to the AFL Championship 13-6. However, if the Chiefs were going to get back to the Super Bowl they would have to beat their Nemeses in Oakland. As if it were pre-ordained the Chiefs defense would be up to the task again, in the game that would be the final game in AFL history, holding the Raiders to just 7 points, to win the final AFL Championship and advance to their 2nd Super Bowl. The Chiefs would become the only AFL franchise to win 3 Championships counting their years in Dallas. 

Super Bowl IV: When the Chiefs participated in Super Bowl I the game was seen as an exhibition more than a championship, as no one gave them a chance to beat the powerful Green Bay Packers. However, after the Jets beat the Baltimore Colts in Super Bowl III the game was viewed as a legitimate championship, as the AFL proved it was on equal footing with the NFL. With a full merger coming this game would be the last AFL-NFL Super Bowl, and the Chiefs used the game as a crusade for the American Football League, and wore patches on their jerseys saying "AFL-10," which referred to the league's 10-year existence. This time the Chiefs opponents were the Minnesota Vikings, and their fierce defense; once again nobody gave the Chiefs a chance to win as they were listed as 12-point underdogs for the game played in New Orleans. However, the motivated Chiefs would take a 16-0 lead into halftime thanks to a Mike Garrett TD, and 3 Jan Stenerude FGs. The Chiefs would seal them game in the 3rd Quarter on a dynamic 46-yard touchdown pass from Super Bowl MVP Len Dawson to Otis Taylor. The Chiefs would go on to win the game 23-7which evened the AFL's record in Super Bowls to 2-2, and once and for all proved the league was for real, and was worthy of the coming merger.