Schroeder was the daughter of a German farmer and local postmaster at Champaign. She had an older brother, Walter, and a twin brother, Don. Dorothy was nine years old when their family moved to Sadorus, Illinois. She attended St. Paul’s Lutheran Church in nearby Sadorus and sang in the choir. By then, she started to play baseball with her two brothers and her father, who had also managed a semi-pro baseball team of Champaign. In 1939, the young girl played on a fastpitch softball team and joined the Illinois Commercial College team in 1940.

At 15, Schroeder decided to play professional baseball after reading about the AAGPBL in a Chicago Tribune advertisement. She personified the family background, values, dreams and aspirations that the AAGPLB founders attempted to cultivate, so that her parents insisted on close supervision before permitting her to join the new league. In 1943, she attended the first tryout camp at Sportsman’s Park in St. Louis, where she competed against 60 girls for one of two roster spots. The final tryouts were held at Wrigley Field in Chicago.

Schroeder entered the league in 1943 with the South Bend Blue Sox, playing for them two and a half years before joining the Kenosha Comets (1945-’47), Fort Wayne Daisies (1947-’52) and Kalamazoo Lassies (1953-’54). In her first season, she led the league shortstops in fielding average, collected 32 stolen bases and hit a respectable .211 of batting average, considering that the league used an underhand pitch in what could only be called classic dead-ball-era fashion. She also had 56 hits with 44 runs and 56 walks to her credit.

In 1944 Schroeder stole 70 bases. Failing to hit .200 in each of her first six seasons and totalling four home runs in that time, she became a fine hitter with power in her later years after the league switched to overhand pitching. From 1949 through 1954 she hit a combined .242 average (509-for-2095); tying for third place with five home runs in 1950, and finishing fourth in 1951 with four homers. In 1952, she was again fourth with six dingers and her average raised to .245, while earning her first of three consecutive selections to the AAGPBL All-Star Team.

In 1953, Schroeder saw her average climb to .285 and tied for fourth with six home runs. She also was named the Most Valuable Player of the Daisies, after helping her team to win the regular season title with a 67–42 mark. But after an exciting series, Jean Faut led the South Bend club to win the Championship Title.

At age fifteen, Schroeder became the youngest founding member of the All-American Girls Professional Baseball League, thus having the distinction of being the only girl to play in the league for its twelve full seasons. A three-time All-Star and ranked in the Top-10 in several offensive categories, she was arguably the top shortstop in league history. After the league folded in 1954, she played four more years on a touring team of 11 All-Americans piloted by Bill Allington across Canada and United States. When the lack of finances caused the tour to end after four summers, Schroeder had played a record 15 seasons of professional baseball.

Schroeder enjoyed her most productive season in 1954, when she posted career-highs with .304, 17 homers and 65 runs batted in. In that season, she was part of a Lassies All-Star slick infield that included June Peppas at first base, Nancy Mudge at second, and Fern Shollenberger at third. Meanwhile, the called Home Run Twins, Chris Ballingall (17) and Carol Habben (15), powered the offense with 32 home runs; Peppas enjoyed a year career, and Kalamazoo advanced to the Championship Series. As a result, the Lassies defeated the Daisies in a best-of-five games series, with a decisive eight-inning RBI double by Schroeder in Game 5, during what turned out to be the AAGPBL final season.

When the league was unable to continue in 1955, Schroeder joined several other players selected by former Daisies manager Bill Allington to play in the national touring team known as the All-Americans All-Stars. The team played 100 games, each booked in a different town, against male teams, while traveling over 10,000 miles in the manager’s station wagon and a Ford Country Sedan. Besides Schroeder, the Allington All-Stars included players as Joan Berger, Gloria Cordes, Jeanie Descombes, Gertrude Dunn, Betty Foss, Mary Froning, Jean Geissinger, Katie Horstman, Maxine Kline, Dolores Lee, Magdalen Redman, Ruth Richard, Jean Smith, Dolly Vanderlip and Joanne Weaver, among others.

Schroeder, who never married, is one of the few All-Americans pictured individually in the exhibit on Women in Baseball at the National Baseball Hall of Fame and Museum in Cooperstown, New York, which was created in 1988. She lived the rest of her life in her homeland of Champaign, working for Collegiate Cap & Gown Company for 36 years until retiring in 1993. She died three years later, at the age of 68, following complications of a brain aneurysm.