Born and raised in the small village of Mosedale, not far from the Roost, Mortimer's family were stonemasons. With his elder brothers both looking to join the family business, the young lad wanted more from life, excitement, adventure, glory, a knighthood. As such, when he was old enough he left to join the Terrick's garrison, hoping it would be his path to his dreams. Turns out, years of walking the walls, maintaining the keep and helping break-up tavern brawls was not quite the path to honour he'd been expecting, nor, can it be said that he truly made a name for himself during those years. It's not that he was bad at it, just he never excelled at any of it. All round satisfactory. Adequate.
Eventually though, Robert Baratheon rose up against the Mad King and war once again came to Westeros. As he marched off with the Terrick levee his old dreams were once again rekindled. After all, what better chance to prove himself. Turns out though, battle wasn't what he had been expecting either and there is a lot that the songs and stories do not mention. By the time the battle of the Trident was won he even made himself scarce for a bit to avoid the flood of knightings that were occurring, just in case someone decided that since he was still on his feet then he might be a worthy candidate.
Before marching he'd done the decent thing and married the lass he'd been courting on and off for years, and when he returned she showed him the twins he'd left her with. He'd thought himself too old to become a father but took to it well enough. His first move was to request a release from his duties in the guard, which was granted. Instead he took a position in assististing the local Sheriff, at first simply providing muscle but later (once he'd learnt to read) also some help with the paperwork as well. The job suited him well, allowing him to exercise the skills he'd learnt in his years of soldiering but with less of the associated risks. There were periods of travel away from the Roost, but no actual night shifts, or drill any more.
When the time the Ironborn landed he was to the east of Terrick lands, helping to deal with a small dispute over a boundary stone. The first they heard of the assault was the vanguard of the refugees and the decision was quickly taken to warn as much of the countryside as possible. He went one way, the Sheriff the other. Making it to Stonebridge a couple of days later with a handful of villagers, he found his boss had not. Nor would he. As the army formed and marched on the reavers he went to, unhappy at the thought of the carnage to come, but even less happy with the idea of what had already happened, and what the future might bring if the invaders were not stopped. A serious head wound at the Battle of Alderbrook took him out of the rest of the conflict and by the time he was back on his feet the army had already left for Harlaw. That suited him well enough though and he moved quickly from Stonebridge where he'd been taken, back home. Reunion with his wife and son followed quickly but was tempered by the news that in the chaos of that morning, his five year old daughter had become lost in the masses, and did not make it into the castle with the others.
With no sign of the Sheriff ever found, he did what he could to keep the peace in the recovering town and lending the skills he'd learnt in childhood to the rebuilding efforts. With the return of Lord Justin he did what he found himself working closely with the youngest of Lord Jerold's sons on a number of matters and eventually played a part in ensuring that he was appointed to the position of Lord Sheriff. Since then there's been bandits, pickpockets, border disputes, and all other sorts of things to keep him busy. Possibly the most noticeable of these though was the incident where a couple of crazy Ironborn were kidnapping small children, during which he spent several weeks involved in the search and lead a party of nobles, knights and one soon-to-be knight to confront the kidnappers and rescue the remaining children.
A serious, weatherbeaten man, with dark but greying hair. A short beard and moustash are similarly coloured and sit at the opposite end of his narrow face. He stands about 5'8" and is not particularly large in build, but the way he holds himself betrays a certain level of worldly experience.
He carries a sword on his hip, it's not a knightly broadsword but nor is it a mere dirk either. Stout, but well worn boots, trousers, tunic and battered cloak complete his outfit with no adornment to be seen on any of it, save a small cloth sash over his belt that displays the heraldry of House Terrick.