But don't completely believe what you see.
Parcells is the iconic, 65-year-old Dallas Cowboys coach who has a 19-year NFL head-coaching pedigree built upon rugged defenses. His reputation is also rugged, hardened by coaching both New York teams for a combined 11 years. Parcells is irascible, often caustic, to inquisitors - many, he believes, try to "antagonize" him.
"A legend," is what Holmgren calls his self-described friend on the eve of their first postseason meeting since the Super Bowl in January 1997.
When people in Dallas kept pressing Parcells this week for comments on the Cowboys losing three of their last four games entering today's NFC wild-card playoff game against the Seattle Seahawks, he said, "If you want to talk about history, go down to the museum."
Holmgren, the 58-year-old Seahawks coach, is a California-bred architect of elaborate NFL offenses that have valued finesse and precision for 21 years, the past 15 as a head coach.
He is a paternal figure around Seattle who rings bells for charity downtown during the holiday season. In November, after Holmgren ripped into his players after a listless, mistake-filled loss at San Francisco, he met with his team the next day and apologized for being so vile.
When Parcells was asked this week if he looks more forward to this postseason opportunity because he knows time might be running out, he said, "Sure, yeah.
"When you get older like I am, and the games get more precious to you, they really do because you don't know how long things are going to go. ... Actually, Mike and I talked about this this past spring at the combine.
"I kind of got the sense that he feels the same way."
Parcells has won two Super Bowls - with the Giants after the 1986 and 1990 seasons - and has coached in a third, which he and his Patriots lost to Holmgren's Packers. With 183 wins, he's second among the NFL's active coaches behind San Diego's Marty Schottenheimer (205), and ninth overall.
Last February, Holmgren became the fifth NFL coach to take two franchises to the Super Bowl. The others are Parcells, Dan Reeves, Don Shula and Dick Vermeil. Holmgren has 158 wins, fourth among active coaches, just behind Joe Gibbs (162) now that Bill Cowher (161) has resigned from the Pittsburgh Steelers.
Holmgren agrees that while he and Parcells have different personalities, they share beliefs.
Parcells, unsolicited, offered a strong opinion when asked to reflect upon his career.
"It's been a great experience for me and a lot of fun and I've met a lot of good people - players, coaches, owners, guys that I like.
"You've got one of them coaching there in Seattle. I think very highly of Mike. I don't know why we hit it off but we did. ... Right now he's the enemy, but I like him."