Lachemann began managing in the Oakland Athletics' farm system in 1973, and switched to the Seattle organization five years later. On May 6, 1981, Lachemann was promoted from Triple-ASpokane to succeed Maury Wills as the M's manager. But during the equivalent of almost two full seasons, Seattle was and in the midst of an eight-game losing streak when Lachemann was fired on June 25, 1983, and replaced by Del Crandall. He returned the following year as manager of the contending Milwaukee Brewers, but the club collapsed to, last in the American League East, and he was fired with three games remaining to be played, though he was allowed to complete the season with the Brewers. Lachemann was a major league coach for the next eight seasons, under John McNamara with the Boston Red Sox and La Russa with the Oakland Athletics. He was the third-base coach with Boston's 1986 American League champions and the Athletics during their three consecutive American League pennants, and their 1989 World Series championship. Lachemann was a key member of La Russa's highly regarded staff.
First Marlins' manager
Due to his success with the Athletics, on October 23, 1992, he became the expansion Marlins’ first manager when they entered the National League at the outset of the 1993 season. He was chosen over candidates such as former major league managers Bill Virdon and Jimy Williams, and also was a finalist for the managerial job with the Texas Rangers, who hired Kevin Kennedy. The Marlins were in their inaugural season, good for sixth place in the NL East while being five games better than the New York Mets. In the strike shortened season of 1994, they went for a fifth place finish. Florida improved to and a fourth-place ranking the following year. For 1996, the team was playing slightly below average, being by the time of the All-Star break. On July 7, Lachemann and hitting coach Jose Morales) were fired. Lachemann was replaced by John Boles, a front-office executive for the Marlins at the time. General manager Dave Dombrowski described the move as an "extremely difficult decision to make at this time," citing the team's play as the reason for the change. Lachemann described his biggest regret that he would not be around to see the team win. As the Marlins' manager, Lachemann compiled a record. The next year, the Marlins won the World Series.
Later coaching career
He returned to the coaching ranks the following season, on La Russa's staff with the St. Louis Cardinals, then coached for the Chicago Cubs and the Mariners, before returning to Oakland in 2005 for three years as bench coach and third base coach. His contract was not renewed after 2007 and he joined the Colorado Rockies' organization in 2008. Lachemann served through 2012 as hitting coach for their Triple-A affiliate Colorado Springs, then was added to the Rockies' MLB staff in 2013 by manager Walt Weiss, a former Oakland shortstop. He worked under Weiss for four seasons, until the Rockies changed managers at the close of 2016. Including a one-game stint as interim manager of the 2002 Cubs, Lachemann's major league managing record was 428 wins, 560 losses.
