"The path on which BJP has chosen to travel, it is natural to appoint a person like Amit Shah as president of the party," Kumar told reporters emerging from Legislative Council.
Describing the appointment as an internal matter of that party, Kumar said he and his party does not intend to interfere in the activities of another party.
Kumar was asked to comment on appointment of Shah, an accused in the Ishrat Jahan encounter case, as BJP president.
Meanwhile, state BJP leaders expressed joy over appointment of Amit Shah as new party chief. Party workers burst crackers and distributed sweets to celebrate the occasion.
Leader of Opposition in Bihar Assembly Nand Kishore Yadav hailed the appointment of Shah.
"He has extraordinary organisational capacity. Due to this quality BJP won 71 out of 80 seats in Uttar Pradesh," Yadav said in a statement.