When Gail Brodsky didn’t receive a wild card into the U.S. Open last year, her father, Eduard, said, she was so disappointed that she cried for two weeks.

This year, all is forgotten. Earlier this month, Ms. Brodsky, a 17-year-old who grew up in an apartment building across the street from Coney Island Hospital on Ocean Parkway in Brooklyn, won the 18-and-under national tournament in Berkeley, Calif., a victory that guaranteed her a first-round match at this year’s U.S. Open, which begins Monday. Yesterday, she posed for pictures with former world no. 1 Jim Courier and Katrina Adams, a former pro and a commentator for the Tennis Channel, at the U.S. Open draw ceremony. She’ll play Agnes Szavay, the no. 14 ranked player in the world, next week.

“It’s always been my dream,” Ms. Brodsky said before her practice session at the National Tennis Center in Flushing on Wednesday. “Ever since I was 6 we’ve been coming here every year. My dad’s clients would always give him tickets because they knew he was so involved in my tennis. Sometimes we would even get box seats.”

Mr. Brodsky’s clients are not investment bankers or hedge fund managers who have financed his daughter’s career. The story of the Brodskys, a Jewish family from Ukraine, is more compelling than that. When Mr. Brodsky arrived in America almost 17 years ago, he left behind his wife and infant daughter. He had $100 and a limited understanding of English. Back home, he was an accomplished competitive rower and an engineer who repaired ventilation systems. In America, he delivered pizzas. He worked for a furniture factory. Soon, he enrolled in a dog grooming school in Manhattan and took a job with Karen’s for People & Pets on Lexington Avenue. In time, Mr. Brodsky obtained his own clients, and when his wife, Julia, a former gymnast, joined him in New York, he taught her the business. Gail stayed in Ukraine with her grandmother for a while longer. When the Brodskys could afford to reunite the family, Eduard reduced his clients by half and began to teach his daughter tennis.

To this day, Mr. Brodsky says, he can barely sustain a rally on the court, but “I’m as good as it gets feeding balls from the basket.” For six years, Ms. Brodsky practiced what she and her father learned from books and videotapes, mostly on public courts in Brooklyn and, in the winter, at local indoor clubs that would comp them time. In the summer, she ran on the beach. At home, she did sit-ups and push-ups and worked with the various fitness equipment her father collected for their small apartment. By age 12, she was one of the strongest juniors in the country and attracted the attention of Mark Weil, founder of the Weil Tennis Academy in Ojai, Calif. Mr. Weil asked her to train at his academy during the winter months, and so Mr. Brodsky and his daughter moved to California each year and lived together in a small dorm room with bunk beds. His wife stayed in Brooklyn and took on as much grooming as she could.

“We knew tennis could open a lot of doors, send her to college,” Mr. Brodsky said.

Earlier this week, though, Ms. Brodsky chose a different path, and with her father’s blessing. She is now a professional player, which means she’ll be able to keep whatever prize money she earns at this year’s U.S. Open. (A first-round loss would deposit $18,500 into her first bank account, which she opened this month.)

Once the tournament ends, the not-so-glamorous life of a rookie touring pro begins. This fall, Ms. Brodsky and her father plan to travel to whatever tournaments they can reach by car. She said it was difficult to turn down a full scholarship to the school of her choice, especially since many of the best professional women leave the junior ranks at an earlier age and establish themselves as top pros at Ms. Brodsky’s age or younger. (Her idol, Kim Clijsters, was a top-20 player before she celebrated her 18th birthday.) Risks aside, Ms. Brodsky says it was an opportunity she couldn’t pass up.

“Even if I go to college and let’s say I want to be a lawyer and study law for four years, I’ve played tennis for 12 years and I’ll never be as good at anything as I am at tennis,” she said. “You only live once.”