Newark Mayor Cory Booker continues to staff up his nascent Senate campaign; he has hired Kevin Griffis to serve as a senior adviser with a focus on communications.

Booker filed paperwork to explore a run for the open New Jersey Senate seat a couple of months ago, and this new hire signals he is continuing to put together campaign infrastructure.

Public polls show Booker with high ratings since he announced a bid for Senate last year. But several other Democratic candidates are considering a bid, including Reps. Rush D. Holt and Frank Pallone Jr., state Assembly Speaker Sheila Oliver and state Senate President Steve Sweeney.

A veteran of of Democratic politics in Virginia, Griffis worked on President Barack Obama’s first presidential campaign, according to a 2012 press release from the Podesta Group. Griffis worked at the Department of Commerce prior to his time at the Podesta Group. In 2008, he served as Obama’s communications director for the tough South Carolina Democratic primary.

CQ Roll Call has profiled Booker’s early hires, although his finance director ultimately opted against taking an official role in the campaign.