Bentley's first memories are that of Happy Camper Orphanage not knowing who his parents were, and if they were alive or dead and if alive where. Well Bentley was the first at the orphanage and that is where Sly, Bentley and Murrary met. They soon became like family. Soon the 3 realized that their skills meshed perfectly together and they soon became The Cooper Gang.
As the yrs went by Sly and Murrary grew bigger and more muscular while he just grew height wise and only by just a bit.
Sly Cooper and the Thievius Raccoonus
The 3 throughout their adventures encounter the members of the Fiendish 5, each time Bentley concocts a plan to get them through each mission against the 5 members.
When Sly was dying from the Poison Gas, Bentley hacked the system and saved his life.
Sly 2: Band Of Thieves
In this one Bentley goes on his first mission and becomes the Team's resident Demolitions expert. In this one he also has greater strategy. As opposed to his being timid in the 1st one he is now on the field working to get the Clockwerk parts.
When the team is captured by the Contessa he is the only member around and he saves them singlehandedly. After that he fights and defeats Rajan amongst other things.
Unfortunately at the end his legs are broken and Murrary carries him away.
In Between Sly 2 and 3
Sly and Murrary recover Bentley from the hospital. Bentley says how he feels like he is a burden to the team to which Sly says no and they take him back to their HQ.
Murrary later on leaves to learn the Dream Time from the Guru and this upsets the team greatly. Bentley also builds and improves his wheel chair turning his weakness into a new strength which greatly enhances manuverability, thief skills, and combat.
He was also with Sly when he heard about the Cooper vault and this became his new obsession and he is the one to tell what they need in the new recruits.
Sly 3: Honor Amongst Thieves
The First thing they do is get Murrary back in the gang and then they travel to the Outback where they free it from the miners and save the Guru. After Guru joins Bentley determines they need a RC specialist and so they travel to Holland where they recruit Penelope.
Bentley next says they need a Demolitions Expert and so they travel to China to get the Panda King...when Sly said no to his joining Bentley insisted he was needed. After saving the Panda King's daughter they travel to Blood Bath Bay where they repay a debt to Dimitri Lousteau and after the debt is paid he joins the gang.
Soon after they go to do the Cooper Vault Job and after various missions Sly fakes Amnesia and Bentley and the Gang split.
Bentley and Penelope stayed together rebuilding the Cooper Vault and improving its security and he is at the end seen writing in the Thievius Raccoonus, showing that Sly thinks of him as a equal and that he thinks of Bentley as his equal.
At the end he is seen building a time machine,