In 1988, an arbitrator ruled that baseball team owners had colluded against the players in an effort to stem free agency. He granted several players, including Gibson, immediate free agency. Gibson signed with the Los Angeles Dodgers.
Gibson joined the Dodgers in 1988, and immediately brought a winning attitude after a publicized blow-up when pitcher Jesse Orosco put shoe black in his cap during a spring training prank. Gibson openly criticized the team, which had finished 4th in the NL West the previous season, for its unprofessionalism. He became the team's de facto leader, and won a controversial NL MVP award after batting .290 with 25 home runs, 76 RBIs, 106 runs, and 31 stolen bases. While he didn't lead the league in any major category, the intensity and leadership he brought to an increasingly successful team likely won him the award over players with more impressive statistics. (MVP runner-up Darryl Strawberry of the New York Mets, for example, led the NL with 39 home runs that season.)
In the 1988 National League Championship Series against the New York Mets, Gibson made an improbable catch in left field at a rain-soaked Shea Stadium in Game 3. Racing back, he slipped on the wet grass and, while on his way down with his knees on the ground and the rest of his body suspended, reached out and made a full extension catch to save a potential Mookie Wilson double; however, the Dodgers lost the game 8–4. In Game 4, his solo home run in the top of the 12th proved to be the winning hit. In Game 5, he hit a two-out three-run homer in the fifth; the Dodgers ended up winning the game 7–4. Nonetheless, his LCS heroics served as but a prelude to the career-defining moment that awaited him in the subsequent World Series.
Gibson is perhaps best known for his one and only plate appearance in the 1988 World Series against the Oakland Athletics. Having injured both legs during the NLCS, Gibson was not expected to play at all. In Game 1, however, with the Dodgers trailing by a score of 4–3, Mike Davis on first base, and two out in the ninth inning, manager Tommy Lasorda unexpectedly inserted his hobbled league MVP as a pinch hitter. Gibson, limping back and forth between a pulled left hamstring and a swollen right knee, made his way to the plate to face Oakland's future Hall of Fame closer Dennis Eckersley. Gibson quickly got behind in the count 0–2, but laid off a pair of outside pitches that were called balls. He then kept the count at 2–2 by fouling off a pitch. On the 7th pitch of his at bat, a ball, Davis stole second. With an awkward, almost casual swing, Gibson used pure upper-body strength—and according to Gibson, advanced scouting-based knowledge of what the pitcher would likely throw with that count—to smack a 3–2 backdoor slider over the right-field fence. He hobbled around the bases and pumped his right fist as his jubilant teammates stormed the field. The Dodgers won the game, 5–4, and won the World Series, four games to one.