"We ask you to enter convictions on all of the counts of the indictment," prosecutor Brenda Hollis said.
The trial started more than three years ago before the Special Court for Sierra Leone.
Taylor, the first African head of state to face an international tribunal, pleaded not guilty on 11 counts of war crimes and crimes against humanity.
"He was at the very centre of the web of the crimes in Sierra Leone," Hollis insisted. "He was the one who had control over the leaders of these groups perpetuating such horrific crimes."
The Sierra Leone civil war claimed some 120,000 lives in the 10 years to 2001, with RUF rebels - Taylor's "surrogate army", according to the prosecution - mutilating thousands of civilians by hacking off their limbs. They also mined so-called "blood diamonds".
Taylor dismisses the claims as "lies", saying he was the victim of a political plot by "powerful countries".
Judge Teresa Doherty declared the hearing closed on Friday, saying the judges will now deliberate in private.
A verdict is expected in about four months.
Taylor's lead counsel, Courtenay Griffiths, told journalists at the court he was confident of an acquittal, citing "the inadequacy of the evidence put before the court by the prosecution and the strength of the defence evidence, which proves Taylor's role in Sierra Leone was entirely peaceful".
"Mr Taylor feels a great sense of relief" at the closure of the case, he added.
Taylor, who has boycotted sessions of the trial, was present in court on Friday, but did not address the judges.
Taylor Timeline1989: Launches rebellion in Liberia
1991: RUF rebellion starts in Sierra Leone
1995: Peace deal signed
1997: Elected president
1999: Liberia's Lurd rebels start insurrection to oust Mr Taylor
June 2003: Arrest warrant issued
August 2003: Steps down, flees to Nigeria
March 2006: Arrested, sent to Sierra Leone
June 2007: Trial opens in The Hague