Balboa, who is of Argentine descent, grew up in Cerritos, Calif., and was a product of the American Youth Soccer Association program in Southern California, where he played for his father, Luis Balboa. Luis was a professional player in Argentina and also played with the Chicago Mustangs of the North American Soccer League.
After playing in college at San Diego State University, Marcelo Balboa anchored the American defense in the 1990 and the 1994 FIFA World Cups (his first cap came on January 10, 1988 against Guatemala). He was named U.S. Soccer Athlete of the Year in 1992 and 1994. In 1995, he became the first U.S. player to break the 100-cap barrier.
Marcelo played for León in the Mexican League in 1995 and 1996, before signing with Major League Soccer and the Colorado Rapids. Balboa played six seasons for the Rapids, leading as the team's all-time leader in many statistical categories. In 1998, he joined Tab Ramos and Eric Wynalda as the first U.S. players to play in three World Cups. Traded to the MetroStars in 2002, Marcelo played only five minutes all year, sitting out the rest with injuries, and retiring afterwards.
Balboa ended his U.S. career with 128 caps and 13 goals, and his MLS career with 24 goals and 23 assists in 152 games. In 2005, Balboa was named to the MLS All-Time Best XI and elected to the National Soccer Hall of Fame on the first ballot along with Nick Folan.
Balboa was known for his bicycle kicks, a near miss in the U.S. win over Colombia in the 1994 World Cup; and a goal for the Rapids in 2000 against the Columbus Crew, named the MLS Goal of the Year for that season.
After the 2004 MLS season, Balboa assumed a front office position with the Rapids. He is also head coach of the Broomfield Blast U16 soccer team in Broomfield, CO.
Balboa debuted as a sideline reporter during ABC's coverage of the 2003 MLS All-Star Game and MLS Cup. In 2004, he became a regular announcer for ABC and ESPN's television coverage of the U.S. national team. Most recently, Balboa has paired up with baseball announcer Dave O'Brien as networks' #1 U.S. announcing team for the 2006 FIFA World Cup.  Balboa has made blunt comments on issues such as Togo's threat to pull out of the competition, as well as the controversial officiating in the first round game between the U.S. national team and Italy.