Dwyer debuted with Cap Anson‘s powerhouse Chicago (NL) team, and in 1890 jumped to the Players’ League, though he missed most of the season. He went 21-18 in 1892, toiling in the NL for St. Louis and Cincinnati. When the pitching mound was moved from 50′ to 60’6″ from the plate in 1893 and the league ERA ballooned, Dwyer survived the transition much better than many pitchers. He went 18-15 in ’93, though his ERA rose from 2.98 to 4.13. Peaking in 1896, he compiled a 24-11 (3.15) mark. In 1899 he became a NL umpire, and, after managing the 1902 Tigers to seventh place, umpired in the AL in 1904. He later became the New York State Boxing Commissioner.