The National League baseball team that plays in Philadelphia changed its name from the Quakers to the Phillies before the 1890 season. That same year, the Cincinnati Red Stockings changed their name to the Cincinnati Reds when they fled the struggling American Association and joined the National League. This change was most likely due to the fact that the Boston Beaneaters (currently the Atlanta Braves) had been known as the Boston Red Stockings as recently as 1882. Nicknames were informal and fluid at the time, but presumably teams wished to avoid confusion with other teams whenever possible.
The Phillies, however, have the distinction of being the baseball team that has existed the longest without changing its name or moving to a different city. They’ve been the Philadelphia Phillies and only the Philadelphia Phillies since 1890. The reason the Reds don’t share that distinction is because of a probably corrupt, almost certainly reckless and undeniably opportunistic United States Senator from Wisconsin named Joseph McCarthy. The fervor whipped up by McCarthy’s accusations of Communist activity led the Reds to become the Redlegs for a period in the mid 1950’s. There doesn’t seem to be a clear timeline for when the Reds officially became the Redlegs, or even if there was such a thing as an "official" team nickname at the time. According to this newspaper article from April 16, 1953 (and read the whole thing, it’s fascinating in hindsight) the Reds front office began asking the baseball world to refer to the team as the Redlegs at the start of the 1953 season, but it appears that many sportswriters ignored the request. That article also suggests that the Reds framed the change not as a response to McCarthyism but as a return to the Reds’ historical roots, but even the author of that article suspects a political motive.
Similarly, there is no clear point in time when the Reds switched back. Most sources list 1958 or 1959. One thing we do know, though: the Reds were the Reds again by 1961 at the absolute latest. The reason we can be sure is because of a Pennsylvania Supreme Court Justice named Michael A. Musmanno. Musmanno wrote a letter to Reds manager Fred Hutchinson just before the start of the 1961 World Series between the Reds and the New York Yankees, asking Hutchinson to change the team’s name from the Reds. Musmanno was honestly concerned that headlines such as "Reds murder Yankees" would send Americans into a panic. It’s worth noting that, besides having been a presiding judge at one of the Nuremburg Military Tribunals, Musmanno was staunchly anti-Communist. While in his letter he seems to make an attempt at being lighthearted about the subject, and he seemed to want the Reds to win, he was probably not joking around in his request at all. Also, he didn’t seem to have much respect for the intelligence of the average American. He needn’t have worried, though, as the Yankees defeated the Reds in five games.
During the Redlegs period, the team did not use the familiar logo depicting the wishbone-C with the word REDS inside of it. They used either the wishbone-C without the word inside, or the throwback mustachioed Mr. Redlegs baseball headed man with "Red Stockings" printed on the chest of his uniform. I couldn’t find any evidence that the word "Redlegs" has ever appeared in any form on a Reds/Redlegs uniform or logo, which leads me to question how committed the organization truly was to this change.
So how did the Redlegs do? Overall, they were 538-540 for a .499 winning percentage between 1953 and 1959. Far and away their best year was 1956, when they won 91 games in a 154 game season, which was only good enough for third place in the eight team National League. Such was life before divisions and wild cards. They finished the season one game behind the second place Milwaukee Braves and two games behind the pennant winning Brooklyn Dodgers, who went on to lose the World Series to the New York Yankees. Incidentally, fourth place in the NL that year went to the St. Louis Cardinals, who finished the year a full 17 games out of first. 1956 also saw the Redlegs’ Frank Robinson win the Rookie of the Year award, a first for Cincinnati, and Redlegs manager Birdie Tebbetts win the Manager of the Year award, which was only the second time a Cincinnati manager took home that honor.
Beyond that, the Redlegs were solidly mediocre. The only other time they finished above.500 was 1957 when they finished in fourth place at 80-74. Ted Kluszewski was still in the prime of his career, finishing second in MVP voting in 1954, when he led all of baseball in home runs with 49. Joe Nuxhall made his only two All-Star game rosters as a Redleg, in 1955 and 1956. The Redlegs’ worst showing was a 74-80 record, which they did twice, in 1954 and 1959, finishing in fifth place both times. In 1958, the Redlegs were so disappointing that former Manager of the Year Tebbetts resigned on August 14. Since Tebbetts had been hired in 1954, he has the distinction of having only managed the Redlegs, and having never managed a single Reds game.
Today, the Redlegs era serves as an interesting insight into a time when the men (and only men) who ran baseball had far less business savvy then they do now. It’s significant that there is no clear division between when the Reds were the Reds and when they were the Redlegs. They evidently never tried to sell official Redlegs t-shirts, hats and shot glasses, and there was no press conference announcing a return to the classic Reds nickname with much pomp and circumstance. In the end, the name lives on in fan blog titles and mascot names, and is yet another strange quirk in the long history of Cincinnati baseball.