Chris Bruen is a lawyer.
That does not say much about why he would get involved in espionage activities until his specialty is mentioned, at which point it becomes a deal more logical. Bruen is described as a "privacy and security law specialist who helped his clients combat hackers and cybercriminals". He is employed by Reynolds, Fincher & McComb, a highly successful and prestigious law firm in San Francisco of which Bruen is a partner.
Bruen was for many years a Department of Justice cybercrimes prosecutor who had amassed an impressive winning percentage. It had been his job to convict hackers. In the private sector he did not change his stance on battling cyber criminals but took a job for the law firm that allowed him to continue his work, this time protecting corporations from illegal intrusions. The work was still very satisfying and the pay was considerably better.
Bruen's interest in, and his terrific expertise in hacking and cyber-intrusion started back in the mid 80s when he was a teenager, tall for his age and rail-thin with acne problems and not much confidence outside of his skills on the keyboard. As such, Bruen and two friends were a trio of successful computer hackers who had for a lark with no other intention prowled cybernetically into the DOD database. They just as quickly got out but not before the sniffers in place has tracked them down. Chris was proud of himself for his accomplishment and scared to death about the ramifications which came a few days later as the FBI knocked on the door. He was charged with violations of the Electronic Communications Privacy Act, got probation and a sealed juvenile record.
He is a good looking man likely in his mid 40's, based on his musings about dating a 25-year old paralegal at his firm who was at least 15 years his junior. He is six years a widower having lost his much loved wife, Tana, to breast cancer. As the series opens he is dealing with that dreaded disease himself, his being thyroid cancer being treated with beta-blockers. This awareness of his mortality and the eventual inevitability of it does not haunt him but it most definitely gives him an interesting perspective on danger.
With computers playing such an inescapable role in every aspect of modern day life and with huge corporations like those of his law firm's clients needing help on a global level to combat the hordes of hackers wanting to steal, harass, or even destroy, Bruen is kept enormously busy. And then you have to consider governments and their own agendas. Bruen is likely to stay in demand, assuming he can stay alive.