The actor, who has lent his voice to Cyril in the FX animated comedy since the first episode, added that the lack of similarity between them makes playing him all the more fun.
Parnell said during a conference call: "Certainly there's some insecurity there that I can relate to. I don't think I'm too much like Cyril otherwise.
"I'm not whiny, I don't think. God, I hope not. I do not commit infidelities. I haven't gone on any missions like an agent. And I don't really know that much about accounting and comptrolling and such. So he's a pretty different person than me, which is also part of what's fun about doing it."
Parnell also said he loves interacting with the characters of Malory (Jessica Walter), Lana (Aisha Tyler) and Archer (H Jon Benjamin).
"Malory is such an evil bitch, so that's very specific to respond to and to deal with - although we did have a romance, a bit of an afternoon of love last season," he commented. "Lana is a very strong, interesting character, and we of course have our history.
"With Archer, Archer is also not the nicest guy and it's fun to play that reaction to him and just let all my feelings about him come out."
Parnell continued: "Cheryl/Carol and Pam and Gillette - they also make me laugh a lot. I don't interact with them as much, I guess, but I don't know that I could pick favourites exactly."
Archer season three continues on Thursdays on FX.
Archer: Season 2 is released on Blu-ray and DVD from March 26 in the UK, courtesy of Twentieth Century Fox Home Entertainment
> Archer Judy Greer: 'Cheryl is still bitchy and crazy'
> Archer star H Jon Benjamin: 'Sterling Archer will never be happy'
Watch a clip from Archer below: