The 49ers announced Smith's honor Wednesday afternoon.
Another NFC West first-round pick, St. Louis' Robert Quinn, was named NFC special-teams player of the week Wednesday.
Smith finished October with 6.5 sacks, one forced fumble, a safety and three passes defensed in four games.
From the 49ers: Smith is the first 49ers player to have two or more sacks in consecutive games since Bryant Young in 2000.
Smith could do worse than to earn mention with Willis and Young, two of the 49ers' best defensive players of the past 15 years.