Winding down as a player, Martin began scouting for the Twins in 1961 and held that position for three quiet years. He had remarried in 1959 and had a son, Billy Joseph. In 1965 he accepted a job as third-base coach for the Twins, where he remained until the beginning of the 1968 season. Then he was sent to manage the Denver Bears, the Twins' top farm club. After a successful season there, he was offered the job as manager of the Minnesota Twins.
Martin brought the team to first place, from seventh the previous year. However, Howard Fox, the Twins' road secretary and an old enemy of Martin's, wanted Martin out. The Twins fired him, but the Detroit Tigers hired him for the 1971 season. Martin came on board, bringing with him his right-hand man, pitching coach and friend, Art Fowler, whom he had met with the Bears in 1968. The two worked wonders with the Detroit team, bringing it up to second place from fourth.
The next year, the Tigers came in first place, even though they lost the playoffs to Oakland. By 1973, however, Martin wanted to trade some aging Detroit players for new blood, but the general manager remained loyal to his longtime players. The team slipped to third place, and Martin, blamed for the downfall, was let go.
One week after Detroit fired him, the Texas Rangers hired Martin as manager. The team did poorly during the first season but in 1974 moved up to second place. By 1975, however, a new owner would not renew Martin's contract giving him control over hiring players. The owner then fired Martin when the team's ranking dropped.