The Cavaliers first began play in the NBA in 1970 as an expansion team. Under the direction of coach Bill Fitch, they compiled a league-worst 15-67 record. However, the team began to build around the 1971 draft pick, Austin Carr.

In the 1975-76 season, with Carr, Bingo Smith, Jim Chones, Dick Snyder, and newly acquired Nate Thurmond, Fitch led the Cavs, as the team is commonly nicknamed, to a 49-33 record, which was the best record in the Central Division. He received the league's Coach of the Year award as the Cavs made their first-ever playoff appearance.

The Cavs won the series against the Washington Bullets, 4-3. Because of the many heroics and last-second shots, the series became known locally as the "Miracle of Richfield." However, hampered by injuries, particularly to Jim Chones, the Cavs proceeded to lose to the Boston Celtics in Eastern Conference Finals of the NBA playoffs.

In the 1980s, new owner Ted Stepien quickly hired and fired a succession of coaches, made a number of poor trades and poor free agent signing decisions. Stepien's poor trades cost the team several first round draft picks, and led to a rule change in the NBA prohibiting teams from trading away first round draft picks in consecutive years. The rule is known as the "Ted Stepien Rule." Stepien threatened to move the franchise to Toronto, but brothers George Gund and Gordon Gund purchased the franchise in the mid 1980s and decided to keep the team in Cleveland. In 1993, Toronto would, in fact, get an expansion franchise, the Toronto Raptors.

In 1986, under the Gund brothers as owners, the team acquired, either through trades or the draft, Brad Daugherty, Mark Price, Ron Harper and Larry Nance. These players (minus Harper, who was traded to the Los Angeles Clippers for the rights to Danny Ferry) formed the core of the team that led the Cavs to eight playoff seasons in the next nine years, including three 50-wins plus seasons. However, in 1989, the Cavs were paired against the Chicago Bulls in the playoffs. It was a best-of-five-series. Cleveland managed to beat the Bulls in overtime, 108-105 and tied the series 2-2. Home court advantage went to Cleveland.

The game was evenly matched, until Cleveland managed to score on a drive and raise the lead by 1, with 3 seconds left. Chicago called time. The ball was inbounded to Michael Jordan, who went for a jump shot. Cleveland's Craig Ehlo jumped in front to block it, but Jordan seemed to stay in the air until Ehlo landed. "The Shot" went in as time ran out, with Chicago winning the series 3-2. The buzzer-beater is considered one of Jordan's greatest clutch moments, and the game itself one of the greatest. But the pinnacle of the Cavs' success came in the 1991-92 season, when they compiled a 57-25 record and advanced to the Eastern Conference finals, losing again to the Chicago Bulls 4-2. Cleveland had no success in the playoffs during this period.

After then, an era of decline came for Cavs. With retirements and departures of Nance,Daugherty and Price, team lost its power and no longer was able even to fight for playoffs, where once they used to be the greatest trouble against the Bulls.

For several years under leadership of point guard Terrell Brandon, Cavs became the most defensive team of NBA, setting its tactics all on defense,being the NBA's least point conceding team. But offensive inproductivity caused Cavs to have no success in this era.

Later on, players like Ricky Davis and Zydrunas Ilgauskas were added to the team, increasing the quality, but without any success.

However, after the Cavs' glory days came several losing seasons. Those seasons saw the Cavs drop to the bottom of the league, becoming a perennial lottery draft team. After another disappointing season in 2002-03, the Cavs landed the number one draft pick in the NBA Lottery. The Cavs selected high school phenom LeBron James.

James' status as both a local star (having played his high school basketball at St. Vincent-St. Mary High School in nearby Akron) and one of the most highly touted prospects in NBA history led many to view his selection as a turning point in the franchise's history. The 2003-04 season offered great hope for the future, as James rose to become a dominating player, winning the NBA Rookie of the Year Award.

Hope was even greater for the 2004-05 season. James blossomed into a superstar, increasing his points average, shooting percentage, assists average, and rebounds average. Despite the loss of Carlos Boozer under very dubious circumstances, James teamed with Drew Gooden and Zydrunas Ilgauskas to form the core of the Cavs team. After a promising start when the team seemed to be locked firmly into the Eastern Conference's 5th playoff spot, the Cavs began a downward spiral that eventually led to the firing of coach Paul Silas and general manager Jim Paxson. The Cavs failed to make the playoffs that year, tied with the resurgent New Jersey Nets for the eighth (and final) playoff spot (the Nets owned the tiebreaker over the Cavs).

The 2005 offseason was one of many changes for the Cavaliers. The team hired a new coach, Mike Brown, and a new general manager, former Cavaliers forward Danny Ferry. The team also signed free agents Larry Hughes, Donyell Marshall, and Damon Jones (four-year, $16 million for Damon) to multi-year contracts. Along with new owner Dan Gilbert, the Cavaliers' front office consists of individuals new to their respective positions. Despite the relative inexperience of many of these newcomers, the franchise sees great hope in rising star LeBron James, whom many have compared to all-time great Michael Jordan.

In March, the Cavaliers clinched their first playoff appearance since the 1997-98 season. They wound up receiving the #4 seed in the Eastern Conference and faced the Washington Wizards in the first round. After the two teams split the first two games in Cleveland, LeBron James scored a game-winning basket with 5.7 seconds remaining in game 3. The Wizards then won game 4 to tie the series. With the series back in Cleveland, the Cavs emerged victorious in the fifth game, 121-120 in an exciting overtime contest that saw LeBron James hit the game winning shot with 0.9 seconds left on the clock. Game 6 also went to overtime, on a Gilbert Arenas three-point shot at the end of regulation to tie the score. In the extra session, however, Damon Jones nailed a long jumper in the final seconds to clinch the game for the Cavs - advancing them into the second round for the first time in 13 years.

In the second round, the Cavs lost the first two games to the Detroit Pistons, but then won the next three, including one at the Palace of Auburn Hills (producing the Pistons' only three game losing streak of the season). However, they lost a close Game 6 at home and then fell to Detroit, 79-61, in game 7. This game produced two records of futility for the Cleveland organization. First, they earned the record for least points scored in a Game 7, and secondly, they tied the record for least points scored in a half with 23.

The two playoff rounds were a showcase for the emergence of LeBron James, which he has achieved many "youngest ever to..." records considering his age (21 in the 2005-06 season). More importantly, it marks the rebirth of a once stagnant basketball franchise.