Warren Michael Lander had earlier pleaded guilty to stealing the man's wallet at knifepoint at Samaritan House in December 2015.

In a brief court session at which the offender appeared by video link in a prison blue fleece, Chief Justice Helen Murrell sentenced him to 25 months in jail, with a non-parole period of 15 months.

Lander has been in jail since his arrest in December, and will be eligible for release in March 2017.

The court heard an intensive correction order - where offenders serve their sentence in the community - was considered, but Lander had no address in Canberra to go to.

He could not stay at one hostel, and the victim of Lander's robbery still worked at the only alternative accommodation at Samaritan House.

Last December, Lander was staying at Samaritan House, run by St Vincent de Paul, when he allegedly walked into the office, asked a staff member for his wallet, and produced a knife.

The worker later told police he felt flustered and wasn't sure whether Lander was going to stab him. He said that Lander appeared calm during the alleged robbery.

Police later picked him up at Hackett shops, where he was drinking bourbon and cola. He said he had left the knife in a flower bed nearby.

He has a conviction for murdering his workmate while the pair were drinking in 1998 at Moonee Ponds in Victoria.

Lander, then 18, was found to have "bit, punched, kicked, struck him with a bottle, and stabbed him repeatedly using two knives", according to remarks made at sentencing in the Victorian Supreme Court.

The second knife was used when the first snapped off at the handle, the court heard in 1999. He then set fire to the flat and disposed of the body and other items by the side of a highway.