DiBernardo, a native of Argentina, moved to the United States with his family when he was sixteen. His family settled in the Chicago area where DiBernardo attended J. Sterling Morton High School West in Berwyn, Illinois. He played soccer both for the school's soccer team and for Sparta, a local Chicago club. DiBernardo attended Indiana University where he played on the school's men’s soccer team for three seasons from 1976 to 1978. He had an immediate impact on the team, helping it to the 1976 NCAA Men's Soccer Championship which Indiana lost to San Francisco. In 1977, Indiana failed to make the NCAA post-season, but DiBernardo was selected as a first team All American. In 1978, Indiana reprised the 1976 season, making it to the championship game, but losing to San Francisco yet again. This year DiBernardo won the Hermann Trophy as the top collegiate soccer player in the country. At the end of the season, DiBernardo left Indiana and turned pro. He finished his collegiate career with 54 goals and 17 assists for 125 points. In 1991, Indiana University inducted DiBernardo into its Athletic Hall of Fame. He was also selected to the Soccer America College Team of the Century.
In February 1979, DiBernardo earned his first cap for the national team, coming on as a substitute for Ty Keough in a loss to the Soviet Union. DiBernardo went on to play every national team game in 1979 and was selected to play for the 1980 U.S. Olympic Team. However, he did not compete in these games, held in the Soviet Union, due to President Carter’s boycott. DiBernardo became an integral part of the U.S. efforts to qualify for the 1982 World Cup and played in the four qualification games in 1980. Unfortunately, the U.S. failed to reach the finals.
By this time DiBernardo had already played a season with the Los Angeles Aztecs, who drafted DiBernardo, of the North American Soccer League. He played the 1979 season with the Aztecs before they traded him and Larry Hulcer to the New York Cosmos. He would remain with the Cosmos from 1980 until 1984 when the NASL collapsed. He had played for the Cosmos as an amateur in the late 1970s. In 1980, he played 29 games and scored 7 goals, adding 13 assists. The 1981 season began well for DiBernardo. He played defense, midfield and forward with the top NASL team until he pulled a hamstring. The injury healed slowly and limited him to only 17 games with the team. In 1982, DiBernardo played only one game after before being badly injured in a hard tackle. Although he recovered from the injury, he never regained his pre-injury quickness or agility. In addition to playing outdoors with the Cosmos, DiBernardo played the 1983-1984 NASL indoor season. In May 1984, the Cosmos asked DiBernardo to take a 20% pay cut. He refused and the team placed him on waivers seven games into the season.
After being cut by the Cosmos, DiBernardo spent the rest of the spring and summer playing with the national team as it prepared for the 1984 Summer Olympics and began the qualification for the 1986 FIFA World Cup. He played two of the U.S. team's games in the Olympics. His last game with the national team came as a substitute in the loss to 1985 World Cup qualification loss to Costa Rica in Torrance which led to the failure of the team to make the finals.
He played the 1985-1986 Major Indoor Soccer League season with the Kansas City Comets. In 1987-1988, he played six games with the St. Louis Steamers before suffering a back injury which finished his playing career.
Since retiring from playing, DiBernardo became a Spanish teacher and soccer coach at Waubonsie Valley High School in Aurora, Illinois beginning in 1991. The team’s highest finish came in 2001 when it took third in the state. DiBernardo also coached the school’s girls team for a single season, 1991-1992. That team went 19-2-3. DiBernardo's Argentinian heritage has aided him with teaching the Spanish language and South American culture.
He also founded the Americas Soccer Club with Rudy Keller, who had played with DiBernardo in their youth club days.
DiBernardo's daughter Vanessa was a member of the US Women's Under-20 National Team that won the Under-20 Women's World Cup in Japan in 2012. Vanessa played for the University of Illinois women's soccer team and currently plays for the Chicago Red Stars.