His name is Steven Gail, but to hundreds of students, Santa Clarita, California’s most beloved substitute teacher is simply “Mr. G.”

Steven Gail, known to his students as "Mr. G" (courtesy of his Facebook fan page)

“He is a legend in this district,” said Brant Botton, an English teacher at Saugus High School. “All the way from seventh grade to senior year, they respect and revere him.”

When they spot him around their junior high and high school campuses, he’s usually greeted with a, “Hey, Mr, G!” “What’s up, Mr. G?” More recently: “How are you feeling, Mr. G?” And always: “Mr. G, are you going to sing for us now?”

For Ms. Hamburger’s Honors Chemistry class, the 60 year old and University of Southern California alum croons “The Periodic Chart Chemistry Doo-Wop,” his rich vibrato lingering on “mercury” and “iron ore.” In AP Geography, he admits that “Learning the Seas Takes the Longest Time” by way of Billy Joel’s “The Longest Time.” Or, on days when he is feeling especially sentimental — and there are a lot of those days lately — he breaks out his signature version of “What a Wonderful World”:

All my Saugus students, I love you

When you graduate, you’ll know it’s true … what a wonderful world it could be.

Mr. G has realized now more than ever that his students already know these words to be true.

To them, Mr. G was never the typical substitute teacher whose arrival signaled an invitation to check out and act out. He engages them as much as their teachers do, learning everyone’s names by the end of the first day. From the time they set foot in middle school until the time they exit high school, they regularly encounter Mr. G and his backwards golf cap and educational jazz standards. He knows something about every subject as a result of his rigorous training on the debate team at USC. To them, he is a cool uncle who played gigs in nightclubs before he could legally drink. And Mr. G knows a thing or two about cool uncles — his own was Nat King Cole’s original bassist.

Mr. G began subbing in 1999 while working three other jobs. He refuses to rest for long, having set a Guinness World Record in 1976 by playing the electronic keyboard for six days straight to raise money for the March of Dimes charity.

At 60 years old, he may sleep slightly more often, but he continues to do just as much good. In February, he took over Brant Botton’s class for two weeks when Botton’s daughter, just turned 1 year old, began having epileptic seizures. Under the leadership of Mr. G and student Madeline Altieri, the class made cards and raised money to buy her toys. Mr. G and Botton became fast friends.

At the time, no one knew Mr. G was battling a disease of his own. Two years prior, he was diagnosed with prostate cancer, but opted not to have surgery because he could not bear the thought of taking time off work.

“Something else will kill you before prostate cancer does,” his doctor said to him. That “something else” showed itself this past summer. During the last week of June, after flying back east to lay his 90-year-old mother to rest, Mr. G returned home for his regular checkup.

“What’s the prog, Doc?” Mr. G asked.

T-cell prolymphocytic leukemia, a rare form of cancer that affects 250 to 500 people a year, eating away at the bone marrow and immune system.

“Should I worry about this more than the prostate cancer?”

“Kinda, we should,” the doctor replied.

In a critical study from 1999, of 91 patients with the disease, two people lived past 14 months.

Mr. G shared the news with Botton in confidence, but had no intention of burdening his students with the information.

“As long as I’m fine, you’ll see me. And when I’m not fine, you won’t see me,” he tells them, now that word has gotten out. “It is what it is.”

Botton was the leak, wanting to do some good for the man who helped him in his own time of need. He told Altieri and Breanna MacLennan that someone dear to them was in need of some “Saugus spirit.” The girls snapped to attention. In two days, without knowing exactly what ailed Mr. G, students dropped $200 worth of coins into piggy banks set up in their English classrooms. By the end of the week, after Mr. G allowed his condition to be known, Saugus spirit translated into $2,100.

Altieri said, “It was an incredible thing to come home and count the money. $60 in quarters … $30 in dimes.”

The entire school presented him with the check at a rally in November.

Mr. Botton said that in his 10 years of teaching at Saugus, he had never seen students organize anything on this scale in so short of time.

As for Mr. G, he could not say much. “I can’t believe what they did. It’s … amazing. It’s … pretty intense,” he said over the phone, his voice trailing off as tears took over.

But that was just the beginning. When 19-year-old Nick Ventura, a former student of Mr. G’s, got word that his favorite substitute teacher was sick, he went straight to his employers at Shave It, a shaved ice eatery in Santa Clarita.

“You don’t find a teacher who goes above and beyond every day, let alone a substitute teacher. Even if I just met him one time, it would be enough to inspire me. His bright smile definitely makes people’s day,” Ventura said.

In November, 1,100 people came to Shave It’s Mr. G fundraiser. The man of the hour sat stationed by the door until an hour and a half past closing time, greeting three generations of families who all knew the singing sub one way or another. The owners, so touched, decided to donate 35 percent of the profits instead of the advertised 15 percent, raising $1,600.

Ventura and Altieri also partnered with The Habit, a hamburger joint, and the popular chain restaurant Chick-Fil-A on fundraisers. They took their cause to talk show host Ellen DeGeneres and are waiting for a reply.

They have no intention of stopping and hope to raise enough so that Mr. G can afford a bone marrow transplant if and when the time comes. Currently, he receives shots in ten-week increments.

But Mr. G does not act worried. When he cries, it is for other people — for his students, who proved they did not need to graduate in order to realize and return his love, or for Mr. Botton’s epileptic daughter.

“I’m 60. Her life is just starting,” he said.

He and his wife of five years, Olga Narozhna, do not talk about his condition much. They do not know how much time he has to live, and he does not subscribe to the clichés about life, be them optimistic or pessimistic. He abhors the suggestion that he should live his life as if it were his last day, or that there is a light at the end of the tunnel.

“Life's a hell of a thing and the only thing I know with certainty is that it's going to be inconsistent,” he said. “And who says the light at the end of the tunnel isn’t a train coming in the other direction?” he said, laughing.

Mr. G said he readily accepts that his role might be to teach students a different type of lesson — that life is not always good.

“If I’m the person to teach them to go through the grieving process, so be it. If I won that lotto, so be it.”

He paused.

“I did win the lotto in some sense.”

Reach contributor Taylor Friedman here.