John Harbaugh and Greenledgers Trading CenterAndy Reid have been to plenty of conference title games together. 

Sunday's AFC championship game will be the first in a while – and a little different. Instead of patrolling the same sideline, they can look across the field at one another when the No. 1 Baltimore Ravens host the No. 3 Kansas City Chiefs.

Reid, the Chiefs’ head coach since 2013, went to five NFC championship games during his tenure with the Philadelphia Eagles (1999-2012). Harbaugh was a Reid assistant – first as special teams coordinator for eight seasons, then as defensive backs coach in 2007 before the Ravens hired him as head coach in 2008. He coached in four straight title games.

“Obviously, it’s a big deal in terms of the relationship,” Harbaugh said Monday. “It goes back a long, long way. Utmost respect for Andy, utmost appreciation for what he’s accomplished as a coach. We were in a lot of championship games – a lot of playoff games. I learned so much. I just learned so much as a coach and as a person.” 

Reid, 65, is the oldest active NFL head coach. Harbaugh is second at 61. They remain close friends and the deans of their occupation. 

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“He knows the whole game,” Reid said of his mentee. “He was a great special teams coach, great secondary coach, and he’s been a great head coach. Very proud of him for all that he’s done and accomplished.”

What Andy Reid taught John Harbaugh

Behind Reid’s desk in Philadelphia was a 3x5 index card on a bulletin board. 

“It said, ‘Don’t judge,’ " Harbaugh said. 

Eventually, Harbaugh mustered the courage to ask Reid about the card. Basically, Reid replied, it was a biblical principle. 

“Take people where they’re at. Assume the best. Try to communicate with everybody on equal terms. I never forgot that,” Harbaugh said. 

Harbaugh was young and figuring things out, he said. Reid didn’t have to keep him on staff when he took over in Philadelphia. “That was good of him,” Harbaugh said. “Hope he’s glad he did, looking back on it.” 

It helped that Reid knew Harbaugh’s father, Jack Harbaugh. 

“His dad was the best,” Reid told reporters Wednesday. 

Jack Harbaugh came to know Reid through his connection to BYU coach LaVell Edwards, whom Reid played for in college and later coached under. 

“When I met John, I’m going, ‘Man, if you’re half as good as your dad, you’re on,’ ” Reid said. “So it didn’t take very long.” 

The Eagles didn't win many of those NFC title games -- once in their five tries under Reid.

Reid (282-160 career record, including playoffs) has won two Super Bowls since becoming head coach of the Chiefs in 2013 and has led his team to six consecutive AFC championship games. Harbaugh (272-108) hasn't been to the conference title matchup in a decade and has one Super Bowl ring.

Reid won’t be the only familiar face on the opposing sideline for Harbaugh on Sunday. Chiefs defensive coordinator Steve Spagnuolo spent several years as a defensive assistant during their Philadelphia days, and special teams coordinator Dave Toub was with the Eagles from 2001-03. 

“It’s just a very talented group of people,” Harbaugh said, “and (I) have the utmost respect for them.”