San Francisco 49ers head coach Bill Walsh, right, and quarterback Joe Montana smile for photographers during the closing moments of their playoff game against the Minnesota Vikings in this Jan. 4, 1989, file photo at Candlestick Park in San Francisco. Walsh, the man who became known as the father of the West Coast offense, died early Monday.

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 and was elected into the Pro Football Hall of Fame in 1993.

He is survived by his wife, Geri, and two children, Craig and Elizabeth.