Bert is an employee of the Caltech geology department who met Amy while she was working there in her own lab in "The Occupation Recalibration". Bert keeps bringing Amy interesting and beautiful rocks every day. It takes Howard and Raj to point out that he likes her. Bert then asks her to a rock and mineral show which she declines because she has a boyfriend. When Bert starts talking abut how no one wants to do anything with him, Amy in a fit of sympathy agrees to go. Unfortunately Bert is taking it as a date. Raj and Howard offer to talk to him to let him down easy and they end up going with him to the show.
Bert also appeared in "The Contractual Obligation Implementation." The same actor played a socially awkward character that Raj met just prior to a library date with Lucy. He tried to crash their date and Raj sent him away. This character is unnamed in the plot, but the closing credits gave the name Bert.
In "The Dependence Transcendence ", Bert hosts a Caltech party and still thinks Amy is so cool.