Lever was selected by the Portland Trail Blazers as the 11th pick in the 1982 NBA draft out of Arizona State. While at ASU, his guard-tandem teammate was Byron Scott, who left school early to sign with the San Diego Clippers. In his debut, Lever recorded 9 points, 7 assists and 4 steals in a road loss over the Kansas City Kings. On January 20, Lever recorded his first career double-double as he puts up 14 points and 13 assists in a road loss over the Mavericks. Three days after, Lever recorded his second career double-double as he recorded 11 points and 10 assists in a road win over the Spurs. On March 20, Lever recorded a season-high 19 points to go along with 6 assists as the Trailblazers picks up the win over the Nuggets. During his rookie season, Lever averaged 7.8 points per game, 2.8 rebounds per game, 5.3 assists per game and 1.9 steals per game.
He was considered one of the NBA's best point guards in the late 1980s while playing for the Denver Nuggets. In his debut with the Nuggets, Lever recorded 14 points and 12 assists in a win over the Warriors. On November 6, Lever recorded a double-double of 24 points and 18 assists in a road win over the Lakers, the first time it happened in Nuggets history. On March 9 against the Pacers, Lever recorded his first career triple-double with 13 points, 15 assists and a career-high 10 steals. On April 10, Lever recorded a double-double of 26 points and 18 assists in a road loss against the LA Clippers. At that time, he joins Magic Johnson as the only players since the ABA-NBA merger to have at least 2 season games having recorded 24 points and 18 assists. In his first season with the Nuggets, Lever averaged 12.8 points per game, 5.0 rebounds per game, 7.5 assists per game and 2.5 steals per game. Next season, Lever continued his impressive or stellar performance for the Nuggets. On November 12, 1985, Lever recorded his first 30-point double-double as he recorded 31 points, 12 assists and 9 rebounds in a road loss to the Rockets. Despite his size he regularly led the Nuggets in rebounding. He is the Nuggets' all-time franchise leader in steals and was 2nd in career assists. He is one of only three players in NBA history to record 15 plus points, rebounds and assists in a single playoff game.
Lever was traded by the Nuggets to the Dallas Mavericks in 1990 for the Mavs' #9 pick in the 1990 NBA draft plus Dallas' first-round pick in the following one. The Nuggets subsequently traded the #9 pick and their own #15 pick to the Miami Heat for the Heat's #3 pick in the 1990 draft, with Denver sending the Mavs' 1991 first rounder to the Washington Bullets along with Michael Adams, for the Bullets' first round pick in the 1991 Draft. Lever sat out the entire 1992–93 season due to knee injury. He finished his career with the Mavericks in 1994 with career averages of 13.9 points, six rebounds, 6.2 assists and 2.22 steals per game.
