Born in Rochester, New York, Wambach was raised in the Rochester suburb of Pittsford. She is the youngest of seven siblings (with two sisters and four brothers) born to Pete and Judy Wambach. She began playing soccer at the age of four after her sister decided she wanted to try the sport. Their mother checked out a book from the library explaining how to play the game, and from then on soccer became part of their family tradition. "I think I was bred to do what I do now", Wambach said in an interview. "Growing up as the youngest of seven was like being in a team environment, you learn all kinds of things ... I learned how to compete, my brothers and sisters always played with me on the same level and they never let me win until I was better than them and deserved it. Being in such a big family makes you humble. You might have a certain skill or talent but there is always someone who is better at something than you."
"She was as competitive as you can get. One of the first experiences where I knew she'd be better than most, was a game of catch football. I threw the ball to one of the neighbors and Abby tackled him. She got up and he was on the ground, groaning. She was 11 or 12. I don't think he was ready to get blasted."
— Matthew Wambach (Abby's brother)
Wambach recalls being toughened up by her elder brothers firing hockey pucks at her for target practice. While playing in her first youth soccer league at age five, she was transferred from the girls' team to the boys' after scoring 27 goals in only three games. As a pre-teen, she began eluding defenders by heading the ball over them and running around them.
Wambach attended Our Lady of Mercy High School in Rochester from 1994 to 1998, where she lettered in soccer and basketball. During her high school career, she scored 142 goals, including 34 in 1997 alone. Mercy's soccer coach, Kathy Boughton, recalled that Wambach would stay after practice to practice diving headers – a skill that would later become her signature as an international player. Following her senior season, Wambach was named to Parade Magazine's High School All-America Team. She was also voted national high school player of the year by Umbro and the National Soccer Coaches Association of America (NSCAA). In 1997, she was named NSCAA Regional Player of the Year, NSCAA State of New York Player of the Year, Gatorade Circle of Champions New York Player of the Year, and cited by USA Today as one of the nation's top 10 recruits.
Wambach was a three-year captain for the Rochester Spirit club team and named All-Greater Rochester Player of the Year in 1995 and 1997. She was a member of the Olympic Development Program (ODP) U-16 National Team in 1996, the 1997 National U-20 Player Pool, and trained and played with the U.S. women's national soccer team while competing in the 1997 U.S. Soccer Festival in Blaine, Minnesota. In 1997, she traveled to Beijing, China, as a member of the first American youth soccer team to ever compete there.
University of Florida Gators, 1998–2001
Considered the top college recruit in 1997, Wambach was intensely sought after by numerous colleges, including top soccer programs such as the University of North Carolina, UCLA, the University of Portland, and the University of Virginia. After sticking with her commitment to her parents to visit five schools, Wambach accepted a full athletic scholarship to attend the University of Florida in Gainesville, where she would play for coach Becky Burleigh's Florida Gators women's soccer team from 1998 to 2001. Florida's program had only been in existence for three years; however, the challenge of joining a less established team over a team like North Carolina with a long history of championship titles appealed to Wambach. As a freshman in 1998, Wambach helped lead the Gators to their first NCAA national championship over the 15-time champion North Carolina Tar Heels. The team also won four consecutive Southeastern Conference (SEC) championships from 1998 to 2001.
Individually, she was the SEC Freshman of the Year (1998), a freshman All-American (1998), a first-team All-SEC selection for four straight seasons (1998, 1999, 2000, 2001), a two-time SEC Player of the Year (2000, 2001), twice received SEC Tournament Most Valuable Player honors (2000, 2001), and was named a first-team All-American her sophomore, junior, and senior seasons in 1999, 2000 and 2001. In addition to leading the Gators to the Final Four of the NCAA Division I Women's Soccer Tournament as a senior in 2001, Wambach set school career records for goals (96), assists (50), points (242), game-winning goals (24), and hat tricks (10). Over ten years later, she remains the Florida Gators' all-time leading scorer with ninety-six goals. Wambach was inducted into the University of Florida Athletic Hall of Fame as a "Gator Great" in 2012.