Nicodemo Ferrer, 74, was recommended by retired Chief Justice Hilario Davide Jr., who now serves as Mrs. Arroyos adviser on electoral reforms.
Ferrer served in the anti-graft court from 2000 until his mandatory retirement in 2002, then returned to private law practice.
Ferrer was a regional trial court judge in Baguio, Benguet and Lingayen, Pangasinan from 1983 to 2000.
He obtained his bachelor of laws degree from the University of the Philippines in 1959 and was in private practice until 2000.
Ferrers late father, Andres, was a former Philippine vice consul to Honolulu and San Francisco, California.
Before Ferrer, Mrs. Arroyos most recent appointee to the Comelec was lawyer and government peace negotiator Rene Sarmiento. He replaced Rufino Javier, who retired in February.
Press Secretary Ignacio Bunye said Mrs. Arroyo wanted to appoint only people with unquestionable integrity to the beleaguered poll body.
Comelec spokesman James Jimenez said Ferrers experience in the judiciary would make him a "valuable member" of the poll body.
"The Comelec is sure that he would bring his expertise here, especially his personal integrity, which made him qualified to take the post," Jimenez said.
The Comelec has faced a credibility crisis since the opposition raised allegations of vote rigging against Mrs. Arroyo last June.
Mrs. Arroyo admitted to an impropriety in making phone calls to an unidentified election official believed to be then Comelec commissioner Virgilio Garcillano.
She said she had asked the official to protect her votes before Congress could declare the winner in the 2004 election. She denied rigging the outcome, however.
Garcillano disappeared from public view during the height of the controversy. He surfaced in November and later denied that Mrs. Arroyo had cheated in the polls.
The opposition has been calling for the relief of Comelec officials appointed by Mrs. Arroyo to restore its credibility.
Mrs. Arroyo has been battling an opposition campaign to force her from office after successfully fighting an impeachment bid in the House of Representatives last year. With James Mananghaya