Batter	Team	Age	Year	HR	Reign	Record breaker
George Hall	Philadelphia Athletics	27	1876	5	3 years	—
Charley Jones	Boston Red Caps	29	1879	9	4 years	6th on July 31 off George Bradley
Harry Stovey	Philadelphia Athletics	27	1883	14	1 year	10th on August 1 off Jack Neagle
Ned Williamson	Chicago White Stockings	27	1884	27	35 years	15th on July 9 off Ed Bagley
Babe Ruth	Boston Red Sox	24	1919	29	1 year	28th on September 24 off Bob Shawkey
Babe Ruth	New York Yankees	25	1920	54	1 year	30th on July 19 off Dickie Kerr
Babe Ruth	New York Yankees	26	1921	59	6 years	55th on September 15 off Bill Bayne
Babe Ruth	New York Yankees	32	1927	60	34 years	60th on September 30 off Tom Zachary
Roger Maris	New York Yankees	27	1961	61	37 years	61st on October 1 off Tracy Stallard
Mark McGwire	St. Louis Cardinals	35	1998	70	3 years	62nd on September 8 off Steve Trachsel
Barry Bonds	San Francisco Giants	36	2001	73	17 years	71st on October 5 off Chan Ho Park