1961-1969: Harmon Killebrew
Harmon Killebrew was the best Minnesota Twins player in the first decade of existence, by far. In fact, he is arguably the best Twin of all time. He is the career leader in a lot of offensive categories for Minnesota and an icon that continues to live on.
During the decade, Killebrew made eight All Star teams, finished in the top 5 in MVP voting five times and won the award in 1969. He hit 362 of his home runs in the nine years he played for the Twins in the 1960s. If you count his year with the Washington Senators in 1960, before the franchise was moved to Minnesota, he had 393 dingers in ten years.
In the 1965 season, Killebrew helped the Twins win their first pennant and come within a few runs of winning the World Series against the Los Angeles Dodgers. Killebrew was inducted into the Hall of Fame in 1984, becoming the first player to be enshrined as a member of the Minnesota Twins.
Killebrew was not only the best player on the Twins during the 1960s, he was one of the best in the league. He easily defined himself as the best Twins player of the decade, even with the presence of Tony Oliva and the best player Twins player of the 1970s on the squad.