He appeared in the very first game, Ankoku Ryū to Hikari no Tsurugi as a playable Ballistician, he is recruited by having Shiida talk to him after someone has visited the house where Anna resides. In the remake, Mystery of the Emblem, he was omitted (along with numerous other characters).
He next appeared in Genealogy of the Holy War, where he appears in front of Linda at the source of the Thracian River, originally intending to join Seliph's Liberation Army but got lost along the way and wounded, eventually deciding to return home to Anna. Linda, who Jake notes how her name sounds familiar, sets him on the right path and in return he gives her an amulet. He later gets lost again and runs into Amid, who reveals himself as Linda's brother. Amid sets Jake back on the right path and Jake in turn gives him another amulet. He thanks the two for their kindness, claiming that when he gets home, he and Anna will have children just like them. In this appearance, Jake used a generic villager appearance.
Jake's next appearance was as a cameo in Rekka no Ken, where he was a member of Fargus's pirates. He appears to greet the ship's passengers if somebody visited Anna at the inn in the Port of Badon and tells you about the shops aboard the ship.
His ending in Fire Emblem: Shadow Dragon notes that he and Anna always dreamed of traveling to far off continents, perhaps referencing to their status as recurring characters.
Jake is a man who, despite being a unit in some games, seems to dislike fighting, as shown in Shadow Dragon, where he states that he isn't "cut out for the military". He also is smitten with Anna (and vice versa), and their relationship is shown frequently throughout the series. Although he does flirt with other girls, Anna does not seem to mind this very much, she even recommends that Marth use this to his advantage.
His looks varies much from game to game. For example: in Fire Emblem: Rekka no Ken, he has brown hair and wears red. Due to hardware limits in Genealogy of the Holy War, Jake used a generic townsfolk portrait. However, he looks dramatically different in Fire Emblem: Shadow Dragon, where he has blue purple hair and more refined clothes of the same color.
Jake is the first ever Ballistician unit introduced in Fire Emblem, and one of only two available within the game(the other being Beck). Unfortunately for Jake, the class is not particularly useful in this game.
While he's certainly usable, Jake comes saddled with problems. To start with, Jake starts with bad stats in everything other than Defense and he has pretty average growths to go with it, but they're all focused in secondary stats. On average, he will never gain enough Speed to break 0 adjusted speed, even at max level with the lowest WeightBallista. He's also incapable of ever Promoting, leaving him with unimpressive stats even at max level. This will become a problem later in the game as enemies get stronger and begin to break his high starting Defense. Even if you attempt to fix this later in the game with stat boosting items, Jake can't fix his Movement. Ballisticians have a crippling Movement of 4 and a Range of 2, meaning that unless you plan to waste turns waiting up for him or use very defensive strategies, it will be a pain just to get him to attack anything. This becomes particularly apparent if a map is Terrain heavy, which severely hampers his capability of getting anywhere. You could give Jake Boots to try and alleviate this, but other characters can make much better use of the item.
On the upside, Ballisticians can deal huge single hit damage to targets and can obtain weapons that can tear through enemy Ballisticians or flying units. If used defensively, they're very good at weakening enemy units into kill range. However, when taken in as a whole, Jake's lack of mobility, inability to Promote, unimpressive stats, and mid-game level 1 recruitment status mean that he's really not worth using.