From Battlestar Wiki, the free, open content Battlestar Galactica encyclopedia and episode guide
Commander Croft is an honorable man who has been through rough situations that have put him at odds with that which he served. Before being court-martialed by the Colonial Military, he served as commander of an ice garrison on Kalpa, having the advanced skills of a demolition and mountaineering expert. He was married to Leda, who apparently had a love/hate relationship with him; this, according to her, "invites trouble".
He was sentenced to the Prison Barge, apparently before it joined the Fleet, for not handing over the spoils of a Cylon-held platinum mine within his sphere of influence. He is selected from Galactica's mainframe for a mission on ice planet Arcta to destroy the deadly Ravashol Pulsar. In return, Adama promises a pardon of all crimes committed before their acceptance of the mission.
During the climb to the mountain's top, where a vent to the pulsar was located, he saves the life of Captain Apollo from the scheming Wolfe and makes sure that the mission is successful. This is in spite of harsh and biting comments from Leda, who asks how he could help the very people that imprisoned him. To Croft, despite his wrong, he is willing to sacrifice his life as he cannot bear to kill his own, unlike Wolfe.
Although their mission is a success, it costs the life of his wife, Leda, who saves him from the armed Command Centurion Vulpa (The Gun on Ice Planet Zero). His future whereabouts are unmentioned for the remainder of the series.