Ruth broke the single season home run record, which was 27 by Ned Williamson, in 1919 when he hit 29 home runs. Ruth then broke his own record when he hit 54 home runs in 1920, 59 in 1921, and 60 in 1927. He broke the career home run record, which was 138 by Roger Connor, in the 1921 season.
Mark McGwire broke Roger Maris' single season home run record of 61 in 1998. McGwire would finish the year with 70 home runs setting the new single season home run record. In 2001 Barry Bonds broke this record by hitting 73 home runs.
Usually. When Barry Bonds broke Hank Aaron's all time home run record, the balls that were used when he was at bat had a number printed on them. The number on the ball that Bonds hit for the record breaking home run was 138.