A 19th century player, Connor began his major league career as a third baseman with Troy, but soon moved to first base, with a short stint in the outfield. Oddly enough, he played second base in 1884 with New York. Mostly Connor was a big bruiser, at 6'3" and 220 lbs. a huge man for the time, and a big power hitter. Home runs were relatively rare in those days but Connor belted several, as well as lots of doubles and triples. He had decent speed and handled himself well in the field. He led the league once in batting average and on-base (1885), twice in slugging percentage (1889-90), and once in park-adjusted OPS (1888). He wasn't often at the top of the league but was usually among the leaders in many offensive categories, and was a centerpiece of several winning teams. His New York Giants were best in the league in 1888 and 1889, as he teamed with Buck Ewing and John M. Ward plus pitchers Tim Keefe and Mickey Welch on one of the early powerhouse teams.
He finished up his career in St. Louis with a struggling team, retiring after 1897. Connor still ranks among the all-time great players.