
1. Josephine Hull, Harvey (and Arsenic and Old Lace)
2. Alice Brady, My Man Godfrey (and The Gay Divorcee)
3. Jean Arthur, The Talk of the Town
4. Katherine Hepburn, Bringing Up Baby
5. Beatrice Arthur, Lovers and Other Strangers (which also features Cloris Leachman)
6. Cloris Leachman, Young Frankenstein
7. Eve Arden, Grease
And, here's my list of my favorite performances by an actor in a comedy, roughly in order:

2. Cary Grant, Arsenic and Old Lace (and Bringing Up Baby, among others)
3. Jimmy Stewart, Harvey
4. Jimmy Cagney, One, Two, Three
5. Peter Sellers, Dr. Strangelove
6. Zero Mostel, The Producers
7. Gene Wilder, Young Frankenstein (and The Producers, among others)
8. Gig Young, Lovers and Other Strangers
9. Jim Belushi, Return To Me (yes, a very idiosyncratic choice, but he steals the show)
10. Barry Fitzgerald, The Quiet Man
R. Balsamo