Lou Avery was a creative director hired to fill the creative absence at SC&P following Don Draper's meltdown with Hershey and Ted Chaough heading up their LA office.
Lou is first seen working for Dancer Fitzgerald Sample, he is at the airport with a large creative team heading for Detroit to secure the Chevy account. He makes some offhand remarks to Don and Roger Sterling, who are also heading to Detroit, and insinuates they have lost Vicks Chemical. In retaliation Roger uses his relationship with Daisy, the airport lounge attendant, to have their bags lost.
Working at SC&P
Following the impressive meltdown of Don Draper in front of the people from Hershey, the other partners enlist the help of Duck Phillips to find them someone to fill the void in the creative department. After his dismissal/suspension is forced upon him Don heads to the elevator and runs into Duck escorting Lou in to meet with the partners. Following Thanksgiving 1968 Lou has been the defacto head of creative in New York, using Don's office and a very different approach to creative which seems old fashioned to Peggy and the other copywriters.
After several months of Lou's tenure as creative director Roger brings Don back without consulting the other partners which outrages Lou and annoys most of the partners. Lou lords over Don by having him report to Peggy in the hope his pride and temperament will lead to him self destructing. Stan Rizzo finds Lou's comic strip in the photocopier and shares it with the other copywriters as a joke leading to Lou chastising his entire team for ridiculing his work, in particular keeping Don from making his flight to LA.
Jim Cutler and Lou plan a meeting with Commander Cigarettes while Don is in LA, where Harry Crane appears at Megan's party and tells him his job is in danger if they get the account. Don hurries back to New York and crashes the meeting, leading to Jim trying unsuccessfully to get him fired. In an effort to keep Don and regain control of the firm Roger negotiates a 51% buyout of SC&P by McCann Erickson, allowing them to remain independent for business conflicts at McCann with Ted and Don signing five year contracts as co-heads of creative. This leaves Lou's future uncertain for the time being.
Move to Los Angeles
In April 1970, following the buyout and his two year contract still in effect Lou is sent to the LA office which is little more than a place to keep him busy until he can be let go. However Lou has been openly ignoring his work and pushing to sell his cartoon to anyone and leave advertising. In June at the same time the remaining partners are trying to move their business to "Sterling Cooper West" to avoid being moved into McCann's headquarters and losing their independence, Lou calls Don to gloat over his success in selling the cartoon. He explains that he is moving to Tokyo to develop 'Scout's Honor' and will be "living his dream".