Bell was initially very sceptical of Sherlock Holmes and his methods; however, after seeing Holmes' deductions proven true, he comes to realise Sherlock's talent as a detective and readily takes advice from him.
Bell takes a bullet literally for Holmes when James Dylan, a former convict out on parole, loses his job and freedom due to statements made by Holmes, and returns to exact payment in "Tremors". Due to his recurring shoulder injury, he initially transferred to an observation rather than investigative role, but was eventually convinced to return to the active NYPD when Holmes argued that he was wasting his talents in this role. Eventually, his shoulder recovered and he was able to return to full-time duty, even assisting Holmes in investigating a case of two stolen zebras when ordered to take a holiday.
Bell believes in a by-the-book approach to his work, and has, when he deemed it necessary, blown the whistle on his fellow officers immoral and/or illegal activities. He is, however, not a fan of Internal Affairs, using the "rat squad" designation when discussing their work with a colleague (and lover) who had been 'outed' by Sherlock as IA.
- Bell is the only main or recurring character who does not represent a character from the original Holmes stories.
- His last name, Bell, could be a reference to Joseph Bell, Sir Arthur Conan Doyle's inspiration for the original Sherlock Holmes.
- His badge number is 42819. ("Details")
- He played Sky Masterson in his high school production of Guys and Dolls. ("Snow Angels")
- As seen in "End of Watch", Bell is a recipient of the U.S. Flag Bar, NYPD Excellent Police Duty, and the NYPD 170th Commemorative Breast Bar.