Zack first appeared in season three along with Brian and Dave. He is the lead guitarist and singer in the band Lane joins, the band later named Hep Alien. He was later revealed to also be one of the main songwriters in Hep Alien, mostly writing songs about girls and naming them after girls.
After Dave leaves for California, the band remains together and get a new member, Gil, who Zack initially does not like. Eventually, he, Lane, and Brian move into a rented house together. He and Brian sleep in bunked beds in the living room while Lane gets the bedroom. He and Brian reportedly eat anything, including lotion on potato chips. During his time living with Brian and Lane, Zack is revealed to be somewhat of a womanizer.
As time goes on, Lane develops feelings for Zack which she eventually finds out are returned. Zack is revealed at this beginning stage to be very slow at processing major decisions. His womanizer ways are quickly ditched, however, as he begins a relationship with Lane and becomes her boyfriend, and later husband.
In the seventh season, Lane returns from their honeymoon pregnant with twins. While Zack continues to act a bit dim, he is caring and dotes on an often highly annoyed pregnant Lane. Late in her pregnancy, he begins working at Luke's in Lane's place and reveals that he is very nervous about fatherhood. Eventually, he and Lane have their twin boys, Steve and Kwan.
Towards the end of season 7, Zack gets an offer to replace the guitarist for an opening band on a tour. He insists as part of the job offer that he is able to bring Lane, Steve, and Kwan with him but Lane eventually decides that she can't manage two infants without her support system at home. She tells Zack he needs to go as it has always been his aspiration to make a living with his music. Zack appears disappointed but still goes, despite not wanting to leave his wife and sons for that length of time.
- Zack likes the banjo and plays in a bluegrass trio, which he was embarrased to tell Lane at first.