Answer by taking a quote from the following article:

Lewis Robert "Hack" Wilson (April 26, 1900 - November 23, 1948) was an American Major League Baseball player who played 12 seasons for the New York Giants, Chicago Cubs, Brooklyn Dodgers and Philadelphia Phillies. Despite his diminutive stature, he was one of the most accomplished power hitters in the game during the late 1920s and early 1930s. His 1930 season with the Cubs is widely considered one of the most memorable individual single-season hitting performances in baseball history. Highlights included 56 home runs, the National League record for 68 years; and 191 runs batted in, a mark yet to be surpassed. "

Wilson made his major league debut with the Giants on September 29, 1923 and became the starting left fielder the following season. By mid-July he was ranked second in the National League (NL) in hitting. He ended the season with a .295 average, 10 home runs, and 57 runs batted in (RBIs) as New York won the NL pennant. In the 1924 World Series he averaged only .233 in a seven-game loss to the Washington Senators.  Multiple stories exist to explain the origin of Wilson's nickname: By one account, a New York newspaper held a nicknaming contest; the winning entry was "Hack" because he reminded many fans of another stocky athlete, the popular wrestler Georg Hackenschmidt. In another version, McGraw is said to have remarked that Wilson's physique was reminiscent of a "hack" (slang for taxicab in that era). Giants teammate Bill Cunningham claimed that the nickname was based on Wilson's resemblance to Hack Miller, an outfielder with the Chicago Cubs. The New York Times printed the first documented usage of "Hack" on June 10, 1924.  Early in the 1925 season Wilson hit the longest home run on record at Ebbets Field against the Brooklyn Robins, but fell into a slump in May, and was replaced in left field by Irish Meusel. On July 2 he hit two home runs in one inning, tying Ken Williams' major league record set in 1922, but his hitting slump continued. In August McGraw told reporters that he had "...made the mistake of rushing [Wilson] along," and sent him to the Giants' minor league affiliate, the Toledo Mud Hens of the American Association. At season's end, a front office oversight--or possibly, deliberate inaction--left him unprotected on the Toledo roster, and the last-place Chicago Cubs acquired him on waivers. "They let go the best outfielder I ever played alongside", said Giants right fielder Ross Youngs, "and they're going to regret it."  During the 1925 World Series -- between the Senators and the Pittsburgh Pirates -- Wilson's son, Robert, was born.

What did he do with the Giants?
Wilson made his major league debut with the Giants on September 29, 1923 and became the starting left fielder the following season.