Jorge Torrez, 25, told U.S. District Judge Liam O'Grady he plans to appeal his conviction. He said he had nothing to say when O'Grady invited him to speak before sentencing.
Amanda Jean Snell, 20, was strangled with a laptop cord in her bedroom at Joint Base Myer-Henderson Hall in the Washington suburbs in Virginia. Torrez lived nearby on the base.
Grady had little choice about following the jury's recommendation on the penalty. Jurors agreed on the death penalty after convicting Torrez of murder, considered his convictions in Virginia and evidence that he killed Laura Hobbs, 8, and Krystal Tobias, 9, in Zion, Ill., in 2005.
Appeals are expected to take years.
Robert Jenkins, a member of Torrez's legal team, said his client denies killing Snell. He said Torrez's attitude is that "if his only two sentencing choices were life imprisonment or death, he preferred death."
Torrez has not been tried for the Illinois killings. Prosecutors there say DNA ties him to the crime.