updated 9:00 p.m. ET July 30, 2007

SAN FRANCISCO - Bill Walsh changed the look of the NFL with his offensive innovations and legion of coaching disciples, breaking new ground and winning three Super Bowls with the San Francisco 49ers in the process.

Nicknamed “The Genius” for his creative schemes that became known as the West Coast offense, Walsh died at his Woodside home Monday morning following a long battle with leukemia. He was 75.

“This is just a tremendous loss for all of us, especially to the Bay Area because of what he meant to the 49ers,” said the 49ers’ Hall of Fame quarterback Joe Montana. “Outside of my dad he was probably the most influential person in my life. I am going to miss him.”

Walsh didn’t become an NFL head coach until 47, and he spent just 10 seasons on the San Francisco sideline. But he left an indelible mark on the nation’s most popular sport, building the once-woebegone 49ers into the most successful team of the 1980s with his innovative offensive strategies.

The soft-spoken native Californian also produced an army of coaching disciples that’s still growing today. Many of his former assistants went on to lead their own teams, handing down Walsh’s methods and schemes to dozens more coaches in a tree with innumerable branches.

“The essence of Bill Walsh was that he was an extraordinary teacher,” NFL commissioner Roger Goodell said. “If you gave him a blackboard and a piece of chalk, he would become a whirlwind of wisdom.”

Walsh went 102-63-1 with the 49ers, winning 10 of his 14 postseason games along with six division titles. He was named the NFL’s coach of the year in 1981 and 1984.

Few men did more to shape the look of football into the 21st century. His cerebral nature and often-brilliant stratagems earned him his nickname well before his election to the Pro Football Hall of Fame in 1993.

He visited with friends until the end. Tyrone Willingham, the former Stanford coach now at Washington, and Stanford donor and alumnus John Arrillaga went to see Walsh on Sunday, presenting him with the Stagg Award for his outstanding service to football.

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Raiders owner Al Davis and Hall of Famer John Madden stopped by Saturday, and Montana on Friday. Hall of Fame quarterback Steve Young was headed to see Walsh on Monday when he received the sad news instead.

“He knew me well before I knew myself and knew what I could accomplish well before I knew that I could accomplish it,” Young said. “That’s a coach. That’s the ultimate talent anyone could have. I said in my Hall of Fame speech that he was the most important person in football in the last 25 years, and I don’t think there’s any debate about that.”

Walsh twice served as the 49ers’ general manager, and George Seifert led San Francisco to two more Super Bowl titles after Walsh left the sideline. Walsh also coached Stanford during two terms over five seasons.

Even a short list of Walsh’s adherents is stunning. Seifert, Mike Holmgren, Dennis Green, Sam Wyche, Ray Rhodes and Bruce Coslet all became NFL head coaches after serving on Walsh’s San Francisco staffs, and Tony Dungy played for him. Most of his former assistants passed on Walsh’s structures and strategies to a new generation of coaches, including Mike Shanahan, Jon Gruden, Brian Billick, Andy Reid, Pete Carroll, Gary Kubiak, Steve Mariucci and Jeff Fisher.

Walsh created the Minority Coaching Fellowship program in 1987, helping minority coaches get a foothold in a previously white-dominated profession. Willingham and Marvin Lewis were among those who went through the program, later adopted as a league-wide initiative.

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In 2004, Walsh was diagnosed with leukemia — the disease that also killed his son, former ABC News reporter Steve Walsh, in 2002 at age 46. He underwent months of treatment and blood transfusions, and publicly disclosed his illness in November 2006.

Born William Ernest Walsh on Nov. 30, 1931 in Los Angeles, Walsh’s family moved to the Bay Area when he was a teenager.

He was a self-described “average” end at San Jose State in 1952-53. He married his college sweetheart, Geri Nardini, in 1954 and started his coaching career at Washington High School in Fremont, leading the football and swim teams.

Walsh was coaching in Fremont when he interviewed for an assistant coaching position with Marv Levy, who had just been hired as head coach at California.

“I was very impressed, individually, by his knowledge, by his intelligence, by his personality and hired him,” said Levy, who coached the Buffalo Bills to four Super Bowls.

Walsh did a stint at Stanford before beginning his pro coaching career as an assistant with the AFL’s Oakland Raiders in 1966, forging a friendship with Al Davis that endured through decades of rivalry. Walsh joined the Cincinnati Bengals in 1968 to work for legendary coach Paul Brown, who gradually gave complete control of the Bengals’ offense to his assistant.

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