Gov. Martin O’Malley appointed Del. Brian J. Feldman on Thursday to fill a Montgomery County Senate seat vacated by Robert J. Garagiola.

Feldman was the unanimous choice of the Montgomery County Democratic Central Committee for the District 15 Senate seat at a meeting on Tuesday night. Another candidate vying for the appointment, Bilal Ayyub, a University of Maryland engineering professor, dropped out of contention last month. He had been recruited by a coalition of minority group leaders.

Feldman, 52, was first elected to the House of Delegates in 2002. He is a former chairman of Montgomery’s House delegation and has served more recently as parliamentarian in the chamber. Garagiola, the Senate majority leader, announced his retirement in June, saying he wanted to spend more time with his children.

O’Malley also met Thursday with two candidates for another vacant Senate seat in District 36, which encompasses all or parts of Kent, Queen Anne’s, Cecil and Caroline counties.

Sen. E.J. Pipkin (R-Cecil) announced his resignation last month to pursue a new career in sports management

The Republican central committees from those counties split over a successor, with Kent and Caroline choosing Del. Steve S. Hershey Jr. (R-Queen Anne’s) and Queen Anne’s and Cecil picking Del. Michael D. Smigiel Sr. (R-Cecil).

Under the state Constitution, the governor gets to pick the winner if there is a tie among central committees in districts that include multiple counties.