The panel of 12 — many appearing startled when they realized they were the jury — stood, raised their hands and were sworn in to serve on the case.
A panel of six alternates remained to be selected. Superior Court Judge Larry Paul Fidler ordered that process to continue on Monday, followed by opening statements on Wednesday.
Spector, famous for his 1960s "Wall of Sound" recording technique, is accused of the fatal shooting of Clarkson, who was found dead in the foyer of his suburban Alhambra home on Feb. 3, 2003, after he picked her up from a nightclub where she was working as a hostess.
The jury includes several county employees, including two engineers, as well as a man who is a network TV producer and has covered high-profile criminal cases.
All of the panelists said they would weigh the evidence carefully and would be fair to both sides. None of them expressed any preconceived opinions on whether Spector was guilty or innocent.
The panel was chosen from among about 100 prospects who filled out questionnaires in advance and then came to court at the start of the week for questioning by attorneys.
Several of the prospects who were dismissed during the process had expressed strong opinions that Spector killed Clarkson or was responsible for her death because it occurred at his home.
One of the last prospects excused for cause was a woman who said she believed he was guilty and could not change that opinion.
"I understand the rules, I just don't think I can," she said when asked if she could put her opinions aside and judge the case fairly.
The judge told the jury that the trial would last about two or three months.
The jury was formed in a process in which prospects were dismissed for cause or through what are called peremptory challenges, those for which neither side has to state a reason.
As the challenges began to shape the potential jury, Spector's prosecutors several times accepted the panel as it was constituted, but when the defense continued to remove certain prospects and replace them with others, the prosecution resumed using their challenges.
Spector was elected to the Rock and Roll Hall of Fame in 1989. His most notable achievements were in the 1960s and '70s. His career tailed off in the 1980s.
Clarkson was best known as the star of Roger Corman's 1980s cult film "Barbarian Queen."