Biden handily won Massachusetts with more than 65% of the vote.
The electors, who were chosen by Massachusetts voters in the Nov. 3 election, gathered Monday at 3 p.m. to cast their votes in the House chamber at the Massachusetts Statehouse.
Before voting, 10 of the 11 original electors had to fill one of the seats left vacant by the death of elector Ronald Valerio of Auburn.
The Commonwealth William Galvin began the process by taking a roll of the electors and announcing the vacancy.
State law allows electors to choose any Massachusetts citizen to fill a vacancy among electors. The Massachusetts Democratic Party has a practice of choosing two alternate electors to attend the meeting, in case of a vacancy.