Gamlen is of the Amell family, who are nobility in Kirkwall. The Amells have an estate in Hightown.
This section contains spoilers for: Dragon Age II.
Gamlen is a member of the Amell family, relatives of the Hawkes, whom they turn to when they flee Lothering and travel to Kirkwall. However, he has gambled away the family fortune, and lost the estate. He now lives in Lowtown. When Hawke arrives to Kirkwall, the City Guard is preventing passage to all Fereldan refugees. In order to get his family in, he commits Hawke and his/her sibling to working with a mercenary/smuggling group for a year.
The human mage warden could be his child as he is the last known Amell.