Freedman took over the Manhattan Athletic Club, which fell into receivership in 1893, as its receiver.
In 1895, Freedman became the principal owner of the New York Giants of the National League (NL), purchasing a controlling interest in the club from Cornelius C. Van Cott for approximately $53,000 ($1,525,764 in current dollar terms). During his ownership of the team, Freedman drew the ire of many of his players for various fines and abuses. In one incident, star pitcher Amos Rusie sat out the entire 1896 season during a feud with Freedman. NL presidential candidate Al Spalding called Freedman an "impossibility in baseball", demanding that Freedman retire from the game. Freedman refused.
With the financial backing of John T. Brush, principal owner of the Cincinnati Reds, Freedman purchased controlling interest in the Baltimore Orioles of the rival American League (AL) on July 17, 1902. The Orioles were in significant debt, reportedly owing $12,000 ($332,169 in current dollar terms). As a result, part-owner and team president John Mahon purchased shares in the team from players John McGraw, Joe Kelley, and Wilbert Robinson, becoming principal shareholder of the Orioles. Mahon, with the controlling interest in the Orioles, comprising 201 of the team's 400 total shares, sold his shares to Freedman.
In the day Freedman owned the franchise, he released the Orioles' best players from their contracts so that they could be signed by their NL teams: Kelley and Cy Seymour signed with the Reds, while Joe McGinnity, John McGraw, Roger Bresnahan, Dan McGann, and Jack Cronin signed with the Giants. AL president Ban Johnson, along with minority owners of the Orioles, took control of the Orioles franchise, which had to forfeit their game that day as they did not have enough players.
Following the 1902 season, Freedman sold the Giants to Brush.
Freedman owned an ice yacht, named "Haze", which won a pennant race in North Shrewsbury, New Jersey.
Freedman was director of the Interborough Rapid Transit Company (IRT). He first became involved in IRT when John B. McDonald sought to include Freedman. Freedman reported that he invested $1.7 million ($47,057,308 in current dollar terms) in the company in 1901 and 1902.
Freedman served on the board of directors of the Wright Company, established in 1909 to market the Wright brothers' airplanes in the United States.
When Freedman died, his estate was worth over $4 million ($94,697,368 in current dollar terms). Samuel Untermyer served as executor of his estate.
In his will, Freedman bequeathed money to build the Andrew Freedman Home at 1125 Grand Concourse in The Bronx. The home was intended to serve as a retirement home. Plans were filed in 1922 to build the home as a four-story brick building, with the cost of construction estimated at $500,000 ($7,154,076 in current dollar terms). The building cost approximately $1 million ($13,974,757 in current dollar terms) and opened in 1924. The Andrew Freedman Home was named a New York City Designated Landmark in 1992.