His playing career spanned 17 seasons, 14 of which were spent in Major League Baseball (MLB) with the St. Louis Cardinals (1972–1973), the Chicago White Sox (1974–1976), the Seattle Mariners (1977–1980), and the Texas Rangers (1981–1985).

[6] During the 1970 season, the Cardinals assigned Stein to the Double-A level to play with the Arkansas Travelers of the Texas League.

With Tulsa that year, he batted .278 with 100 hits, 26 doubles, four triples, five home runs, and 36 RBIs in 103 games played.

During spring training in 1973, the Sarasota Herald-Tribune labeled Stein as the Cardinals candidate for pinch hitting off the bench.

He made his season debut on April 6 as a pinch hitter, going hitless in one at-bat against the Pittsburgh Pirates.

While in the majors that season, Stein compiled a .218 batting average with four runs scored, 12 hits, two doubles, and two RBIs in 32 games played.

On September 25, Stein was traded by the St. Louis Cardinals to the California Angels in exchange for Jerry DaVanon.

[13] California then traded Stein to the Chicago White Sox on April 3, 1974, before he made an appearance in the Angels organization.

[13] Stein started the 1974 season in the White Sox minor league system with the Triple-A Iowa Oaks.

Stein led the American Association in hits; was second in runs scored, plate appearances (594), at-bats (554), and doubles; and was tied for second in triples.

[16] In the majors that year, Stein batted .276 with five runs scored, 12 hits, one double, and five RBIs in 13 games played.

On August 17, in the first game of a doubleheader against the Boston Red Sox, he hit a game-winning single in the ninth inning to score Pat Kelly.

[21] In August, United Press International noted that it was the first time in his major league career that Stein was getting a chance to start regularly.

[23] "The only thing Darrell Johnson, the Mariners manager told me is to work at third base [...] You get worn out if you just sit on the bench.

[24] Stein stated he was "glad" that the Mariners drafted him, because he did not like playing at Comiskey Park, the home of his previous team, the Chicago White Sox.

[25] He was profiled by the Associated Press during spring training in 1977, and was interviewed about his new team and his unique versatility in the field.

[7] Stein mentioned to the reporter that although he had played a wide variety of positions in the past, he hoped he would get a chance to be the Mariners starting third baseman.

[25] The Mariners manager, Darrell Johnson, praised Stein for playing "good ball" with Seattle.

[32] On August 25, he broke up Dennis Martínez's potential no-hitter in the seventh inning of a game against the Baltimore Orioles.

[39] On July 28, Stein broke up a no-hit bid by Cleveland Indians pitcher Len Barker.

[42] On April 16, 1982, in a game against the Milwaukee Brewers, Stein hit a game-winning double in the top of the ninth inning.

[47] In 85 games that year, Stein batted .239, the lowest average of his career since the 1972 season where he played with the St. Louis Cardinals.

[48] In March 1983, Stein praised the Texas Rangers new manager, Doug Rader, for working on the game in a "serious" way.

[49] On May 18, in a game against the Cleveland Indians, Stein was brought in as a pinch hitter during the 14th inning, and proceeded to get the game-winning hit for the Rangers.

After the season, Stein spoke out against a transaction that the Rangers made, trading Jim Sundberg to the Milwaukee Brewers, calling him a "mainstay of the organization".

Before the 1985 season, it was announced that the Texas Rangers had traded Stein to the Pittsburgh Pirates in exchange for a player to be named later, pending a physical.

[55] The Pirates later canceled the trade after team doctors discovered a "probable disc problem" in his back.

[58] In 1987, Stein coached the Rockledge High School baseball team, leading them a district title with a 17–11 record.

[70] After considering taking a year off of baseball in 1994, Stein eventually accepted the managerial position with the independent league Tyler WildCatters.