For preying on such vulnerable victims - and given his criminal record that began as a juvenile and included more than a dozen convictions - Walker should be sentenced to 57 to 114 years, Assistant District Attorney Ashley Lynam had argued.
"The defendant's record clearly shows a lifetime of criminal involvement," said Lynam, who added that Walker has been deemed by the court to be a sexually violent predator under Megan's Law.
Defense attorney Catherine Berryman said he should have been sentenced to 15 to 30 years because he had taken responsibility for his actions by pleading guilty.
She noted that Walker was also mentally disabled with a low IQ score of 81, has suffered from drug addiction, dropped out of school in seventh grade and was abused by his father and abandoned by his mother.
Two of his victims - who appeared somewhat disoriented - came to court and gave victim-impact statements before sentencing. "I'm having difficulty sleeping and I'm suffering from depression," one woman said.
"This guy was helping me out . . . and he raped me," the other woman said.
For his part, Walker told the court that being locked up for the past year and a half had helped him clear his mind and get in "touch with my higher power."
He apologized for attacking his victims and said he wouldn't want anyone to do the same thing to his 20-year-old daughter or his four sisters.
One sister, Sharonda Williams, fought back tears as she testified about how Walker helped raise her and their siblings and how he looked after their grandmother, who lives in a nursing home.
"The monster that is being portrayed today, I would have never known," she said.
On Twitter: @MensahDean