Matt Keough's journey in Major League Baseball began when he was drafted by the Oakland Athletics in 1973. Initially, he played as an infielder, but his career took a different path when he transitioned to pitching. This change proved to be a turning point, as he made his MLB debut with the Athletics in 1977 as a pitcher.

Keough's rookie season in 1978 was marked by promise and potential. He was named to the American League All-Star team, an impressive feat for a newcomer. That year, he posted a 3.24 ERA and recorded eight wins, showcasing his ability to compete at the highest level. However, the following season was challenging, as he struggled with control and consistency, leading the league in losses with 17.

Despite these setbacks, Keough continued to persevere. In 1980, he experienced a resurgence, winning 16 games and maintaining a 2.92 ERA. His performance helped the Athletics secure a second-place finish in the American League West. This season was a highlight in his career, demonstrating his capability to bounce back from adversity.

Keough's tenure with the Athletics lasted until 1983, during which he experienced both highs and lows. His time with the team was characterized by fluctuating performance, with moments of brilliance interspersed with struggles. In 1983, he was traded to the New York Yankees, marking the beginning of a new chapter in his career.

With the Yankees, Keough's performance was mixed. He spent parts of two seasons with the team, but injuries and inconsistency limited his effectiveness. In 1984, he was traded to the St. Louis Cardinals, where he faced similar challenges. His time with the Cardinals was brief, and he was released after the 1985 season.

Keough's career continued with stints in the minor leagues and a brief return to the majors with the Chicago Cubs in 1986. However, he was unable to recapture the form that had made him an All-Star earlier in his career. After his time with the Cubs, Keough played in Japan for the Hanshin Tigers, where he found some success and extended his professional career.

Throughout his time in baseball, Keough was known for his tenacity and ability to adapt to different roles and teams.