A photo of John O'Neill and his dog Idaho Jack that was taken in Idaho on Christmas Eve, 2006. Photo courtesy of O'Neill family

John O'Neill was a man who loved dogs and would do anything for them.

What he did last week on a busy San Francisco street for his dog, Cappy, cost him his life.

O'Neill, a 47-year-old building contractor from San Francisco, was walking Cappy on San Jose Avenue on Thursday. Cappy was a dog that O'Neill acquired a few weeks ago after his previous dog, a terrier named Idaho Jack, was struck and killed by an N-Judah streetcar.

Ever since that accident, O'Neill blamed himself for Idaho Jack's death, his brother James O'Neill said.

"He was torn up about it," O'Neill said. "He blamed himself for what happened. He was so upset he couldn't talk about it."

John O'Neill kept a close eye on Cappy, and he worried about his dog's safety in busy San Francisco.

But he walked Cappy every night just the same. And he was walking Cappy on Thursday evening, as usual, when somehow Cappy broke free of his leash.

The dog raced into traffic on San Jose Avenue near Bosworth Street. Horrified, O'Neill dashed into the roadway after him.

He followed Cappy into the streetcar tracks that run down the middle of San Jose Avenue. On that stretch of roadway, streetcars operate on a separate right of way and usually travel at a brisk speed.

O'Neill grabbed Cappy and clutched him to his breast. Somehow, he failed to notice the rapid approach of a northbound J-Church.

At the last moment, O'Neill turned and saw the speeding streetcar. Just before impact, he managed to hurl Cappy out of harm's way. An instant later, O'Neill was killed.

"It's unbelievable," James O'Neill said. "It's tragic and senseless and unbelievable. He was my brother, and he was my best friend."

John O'Neill, a native of Vancouver, British Columbia, came to San Francisco with his family as a 4-year-old and attended St. Cecilia School. He graduated from St. Mary's College in Moraga before joining the family construction business, helping his father build apartment buildings around San Francisco. He often brought his dogs to the construction sites, where they would scamper about while O'Neill worked.

He was a sailor, a skier, an outdoorsman, a world traveler, a reader of historical novels and a lifelong fan of the Giants and 49ers. And he liked dogs, especially clean dogs. He often took showers with Cappy, his brother said, and neither dog nor master found that to be odd.

O'Neill is survived by his mother, Maureen, and by his siblings Marlene, James, Barbara and Martha, and by his fiancee, Maritza Perez.

"He was a wonderful man and a wonderful brother," James O'Neill said. "And he sacrificed his life for his dog."

A memorial service will be held today at 6:30 p.m. at St. Cecilia Church, 2555 17th Ave., San Francisco.

Cappy, who was not hurt, is being cared for by a family friend.