|First appearance||"The Rock"|
|Voiced by||Jeffrey Tambor|
|Occupation||Head of ODIN|
Malory Archer (former lover)Anastasia (deceased wife)
Leonard "Len" Trexler is the head of ODIN. He is voiced by Jeffrey Tambor. Len lives and works in Paris at ODIN Headquarters. His right hand man at ODIN is Barry Dylan. He is a polo enthusiast and frequently takes practice shots from atop his desk out this upper floor window into the city. Len is one of the three possible fathers of Sterling Archer.
Len often professes his love for Malory, and in the episode "A Going Concern" it is revealed that he is even willing to marry her, despite knowing she only wanted to marry him for his money. His love runs out when Sterling and several of the other ISIS employees put a Soviet mind control microchip in his head to make him fall out of love with Malory (and unintentionally drive him insane). He is the last known owner of Rabbert Klein.
- In the season 2 episode "Placebo Effect", Trexler is present with Malory during the flashback to Kreiger's 15th birthday.
- Possibly codenamed "Z" as ODIN's head was identified as such in "Killing Utne". But this is likely to be a placeholder as Trexler hadn't yet appeared or been mentioned directly.
- Despite his status as one of ODIN's top agents, Trexler openly disliked Barry, often referring to him as an "ass."
- Trexler has not been seen following his brain surgery, and it is unknown if he is still the head of ODIN.
- Jessica Walter and Jeffery Tambor were also on Arrested Development as husband and wife George and Lucielle Bluth.