Jim Johnson frustrated opponents and confused young quarterbacks with his complex defensive schemes, always looking for a new way to disguise a blitz.
He never ran out of ideas or the desire to coach, even when he had more pressing concerns. In his final days, he was concerned about the start of training camp.
Johnson, whose attacking defenses helped the Philadelphia Eagles to one Super Bowl appearance and five NFC title games, died on Tuesday. He was 68.
"There's been no finer coach or man than Jim Johnson," team chairman Jeffrey Lurie said. "The Eagles family has been blessed and everyone who's surrounded the football team or surrounded Jim in everything he conducted himself, we had a true gem here and there aren't a lot of Jims."
Johnson had taken a leave of absence from the team in May as he continued to battle a cancerous tumor on his spine. On Sunday, the Eagles announced that Sean McDermott would replace Johnson.
A veteran of 22 years as an NFL assistant, Johnson was considered one of the top defensive minds in the league. His defenses consistently ranked among the best in the league, including last season, when the Eagles finished third in total defense and fell one victory short of the Super Bowl.
From 2000-08, Johnson's Philadelphia defenses ranked second in the NFL in sacks (390). During his 10-year tenure, the Eagles made the playoffs seven times and he produced 26 Pro Bowl selections.
"This whole Eagles-Andy Reid regime here that's taken place wouldn't have been possible without Jim," said Andy Reid, who hired Johnson to be his defensive coordinator shortly after he got his first head coaching job with the Eagles in 1999.
"I'm not sure there's a person that I've met that isn't a Jim Johnson fan. He really represented everything this city is all about with his toughness and grit. That's the way he fought this cancer."
Reid and team president Joe Banner visited Johnson in the hospital on Monday. Reid said he spoke with Johnson a few days before the visit and football was on his mind.
"He was very concerned about the starting date of training camp," Reid said. "He had all the dates down and he knew them. Amazing."
NFL Commissioner Roger Goodell praised Johnson for his leadership skills.
"He was a teacher to many players both on and off the field and devoted his life to the game of football," Goodell said in a statement. "He had a positive influence on scores of young men, and leaves behind a wonderful legacy."
In his first news conference as coordinator, McDermott gave full credit to Johnson.
"What haven't I learned from Jim?" McDermott said. "I don't think it would be fair to Jim, in this setting, to try and limit in one statement, one press conference, the effect that Jim has had on my life."
Coaches across the league paid homage to Johnson's impact on their careers and the league.
"He made me believe I could coach at this level," said Ravens coach John Harbaugh, an Eagles assistant for nine seasons with Johnson. "In football, he was a pioneering and brilliant strategist, changing the way defense is played in the NFL."
"He was a dear friend and a special person," said St. Louis Rams coach Steve Spagnuolo, a member of the Eagles defensive staff under Johnson for eight seasons. "Jim meant the world to me, both personally and professionally."
Johnson had been treated for melanoma in 2001.
In January, he complained of back pain and coached from the press box in the Eagles' playoff win over the New York Giants and in the loss to the Arizona Cardinals in the NFC championship.
An MRI after the divisional playoff win against the Giants on Jan. 11 alerted doctors that something might be wrong. Following the Arizona loss, the team announced the cancer had returned and Johnson would undergo more treatments.
Johnson had recovered sufficiently to coach during the team's first post-draft minicamp in May. But he moved around on a motorized scooter during practices and said he wasn't certain he'd be able to return for the season.
"Jim was tailor-made to coach in Philadelphia," said Broncos safety Brian Dawkins, who played 10 seasons for Johnson in Philadelphia. "He was a tough coach who wasn't afraid to let you know how he was feeling, but at the same time, he cared about us deeply."
Johnson is survived by his wife Vicky, two children and four grandchildren.
AP Sports Writer R.B. Fallstrom in St. Louis contributed to this report.