Patil succeeds former revenue minister Eknath Khadse who resigned last month after a string of allegations including one involving alleged irregularities in MIDC land.
"Congratulations to Chandrakantdada Patil on becoming the Leader of the House (Maharashtra Legislative Council)," Chief Minister Devendra Fadnavis tweeted.
Earlier in the day, senior NCP leader Ramraje Naik Nimbalkar was unanimously re-elected as the Chairman of the Council at a one-day special session of the upper house here.
The monsoon session of the state legislature will begin in Mumbai on July 18.