Pat Zachry's journey in Major League Baseball began when he was drafted by the Cincinnati Reds in the 19th round of the 1970 amateur draft. His debut came on April 11, 1976, with the Reds, a team that was part of the legendary "Big Red Machine" era. Zachry quickly made a name for himself as a rookie pitcher, contributing significantly to the Reds' success that season.

In 1976, Zachry shared the National League Rookie of the Year award with Butch Metzger of the San Diego Padres. His performance that year was instrumental in helping the Reds secure the National League pennant and ultimately win the World Series against the New York Yankees. Zachry's rookie season was marked by a 14-7 win-loss record and a 2.74 ERA, showcasing his potential as a reliable starting pitcher.

The following year, in 1977, Zachry was involved in a major trade that sent him to the New York Mets. This trade was part of a deal that included Tom Seaver, a future Hall of Famer, moving to the Reds. Zachry's time with the Mets was a period of both challenges and growth. While he struggled with injuries and inconsistency, he also demonstrated flashes of brilliance on the mound.

During his tenure with the Mets, Zachry's performance was a mix of highs and lows. He pitched a memorable game on July 24, 1978, against the Pittsburgh Pirates, where he struck out 12 batters, a career-high. However, injuries, including a broken foot in 1978, hampered his ability to maintain consistent form. Despite these setbacks, Zachry remained a key part of the Mets' pitching rotation through the early 1980s.

In 1982, Zachry was traded to the Los Angeles Dodgers, where he continued his career as a pitcher. His time with the Dodgers was relatively short, and he was primarily used in a relief role. Zachry's final stint in Major League Baseball came with the Philadelphia Phillies in 1984 and 1985. Although his role was limited, he provided veteran experience to the pitching staff.

Throughout his career, Zachry was known for his tall, lanky frame and his ability to throw a fastball with deceptive speed. His pitching style relied on mixing speeds and keeping hitters off balance. While injuries and team changes affected his career trajectory, Zachry's early promise and contributions to the Reds' 1976 championship season remain highlights of his time in the majors.