Los Angeles Lakers
The Lakers were coming off a league-high 53-win season, but had been eliminated 4–0 in the Western Conference finals by the eventual NBA champion Portland Trail Blazers. Wilkes was the top-rate forward that Lakers head coach Jerry West coveted. Wilkes' career with the Lakers began solidly in 1977–78, but a broken finger and other injuries limited him, and he was out much of the second half of the season, finishing with 51 games played and averaging 12.9 points. An anonymous team official accused him of malingering, and Lakers fans thought he was overrated. He bounced back the following season with his best pro season to date, averaging 18.6 points per game and shooting 50.4%. For a five-season span from 1978 through 1983, he was the Lakers' second-leading scorer behind Kareem Abdul-Jabbar.
Wilkes was a free agent leading up to the 1979–80 season, and new Lakers owner Jerry Buss made it a priority to re-sign him. Los Angeles traded 6-foot-4-inch (1.93 m) Adrian Dantley to Utah for 6-foot-9-inch (2.06 m) Spencer Haywood, the Lakers' first bona-fide power forward since Wilkes joined the team, freeing him to move to small forward and relieved from guarding players as much as five inches (13 cm) and 50 pounds (23 kg) bigger. Wilkes had been playing power forward his entire NBA career. He re-signed to a reported long-term deal at $600,000 per year. The Lakers also added Magic Johnson that year, drafting him with the first overall pick. Head coach Jack McKinney was injured midseason in a bicycle accident and was replaced by assistant Paul Westhead. Released from the rigors of playing power forward, Wilkes blossomed with the Lakers' fast break, averaging 20 points per game and shooting 53.5% that season. He helped the Showtime Lakers win three NBA championships (1980, 1982, 1985). One of the most memorable games of his career was the series-clinching Game 6 of the 1980 NBA Finals against the Philadelphia 76ers; Wilkes had a career-high 37 points and 10 rebounds, but was overshadowed by the rookie Johnson, who started at center in place of an injured Abdul-Jabbar and finished with 42 points, 15 rebounds, and seven assists. "Jamaal Wilkes had an unbelievable game", said Johnson in 2011. "Everybody talked about my 42 [points], but it was also his [37-point effort]."
Wilkes had his best offensive season in 1980–81, when he averaged 22.6 points, which ranked 11th in the NBA, shot 52.6% and played in the 1981 NBA All-Star Game. However, the Lakers were eliminated in the first round of the playoffs by Houston in a best-of-three series. Soon before the start of training camp in 1981–82, Wilkes' eight-day-old daughter died, his second child to die as a baby. He started the season slowly, culminating with a 1-for-10 shooting performance in a 128–102 loss to San Antonio on November 10, 1982. He seriously considered quitting basketball. On November 18, Johnson demanded to be traded, but Buss instead fired Westhead, who was replaced by assistant Pat Riley. Wilkes recovered to average 21.1 points and shoot 52.5% as Los Angeles advanced to the 1982 NBA Finals, where they faced Philadelphia again. He scored a team-high 27 points in game 6 as the Lakers won the series 4–2. In 1982, Wilkes signed a long-term contract extension with the Lakers. They selected James Worthy with the first overall pick of the 1982 NBA draft, which they acquired from a trade made three years before. Although Wilkes was still in his prime, the Lakers valued Worthy's potential to play either forward position and backup Kurt Rambis at power forward. Wilkes received his third All-Star selection in 1983.
In 1983–84, Wilkes missed seven regular season games and the first seven games of the playoffs due to a gastrointestinal virus. After initially missing three games in late February 1984, he returned to play for a month before being sidelined for another four games. In the five previous seasons since 1978–79, he had missed just three games out of 410 and twice led the team in minutes played. Wilkes finished the regular season averaging 17.3 points, and led the team in scoring 18 times, but none after February 28, as the infection began taking its toll. With persistent headaches, stomach cramps and cold chills, he thought he had the flu at first. Antibiotics from team doctors failed to make him better, prompting him to visit his own physician, who linked his condition to a parasite. Upon returning in the playoffs on May 8 against Dallas, Wilkes received a standing ovation from the Forum crowd. Out of shape after the layoff, he saw limited play and averaged only 4.5 points in 14 games while shooting just 40%. He had entered the postseason with a streak of 58 consecutive games scoring 10+ points in the playoffs. Meanwhile, Worthy shined at small forward and was a key for the Lakers while starting in the finals against the Boston Celtics.
After hearing his name in trade rumors during the offseason, Wilkes began the 1984–85 season starting at forward along with Worthy. After the Lakers began the season with a 3–5 record, Wilkes lost his starting spot to Larry Spriggs. His play eventually improved, peaking with a season-high 24 points in a win over Portland on January 29, 1985. Three days later against New York at the Forum on February 1, ligaments in his left knee were torn when the Knicks' Ernie Grunfeld ran into him, and Wilkes missed the final 40 games of the regular season and the entire playoffs. He finished with then-career-lows of 42 games played and 8.3 points per game, but the Lakers won the 1985 NBA Finals over the Celtics with Worthy as one of their leaders.
Wilkes' leg atrophied, and he had to learn to walk again. After he played in the Southern California Summer Pro League and rehabilitated his knee, the Lakers waived him on August 28, 1985, with three years and $2.4 million remaining on his guaranteed contract. The team attributed the move to the NBA salary cap, freeing him to negotiate with any team without his Lakers' salary affecting that team. Wilkes also became expendable after they drafted A. C. Green.