In the early 1900s there were four brothers from the O’Neill family that appeared in the major leagues. Except for the Delahanty family with five brothers, the O’Neills had the most siblings to play in the big leagues. Their roots had Irish beginnings, as two of the brothers, Mike and Jack, were born in Ireland.
Three of the O’Neills,(Mike, Jack, and Jim) had relatively brief careers. Steve had the most extensive baseball career having played for 17 years (1911-1928) and managed for 14 seasons (1935-1954).
Read more about the O’Neill brothers at the link below from The 42: