Ad-tech veteran Michael Barrett is taking over as CEO of Millennial Media, the company said Monday.

Mr. Barrett, most recently the Chief Revenue Officer at Yahoo, is replacing Paul Palmieri, the company's founder, who resigned from its board of directors as well. Marissa Mayer ousted Mr. Barrett soon after she took over as Yahoo CEO, replacing him with Henrique de Castro, whose Yahoo tenure ended abruptly two weeks ago.

"I couldn't be more bullish on the opportunity to monetize the mobile experience and I think by and large you think most people are," said Mr. Barrett.

To succeed at Millennial, Mr. Barrett will have to position his company's offering next to those of mobile giants such as Facebook, Google, Twitter and Pandora. In an interview with Ad Age, he deflected questions about Millennial Media's reliance on banner ads, and how it will fare against ad-tech companies making large investments in cross-device advertising.

"We're actually a leader right now in terms of many native formats, in terms of a lot of bleeding edge creative, and I think that really speaks to the strength of the company," Mr. Barrett said. He also noted that cross-device ad selling is "an important piece of our business and it will continue to grow in importance."

Mr. Barrett's resume is impressive. Before his stint at Yahoo, he served as CEO of Google-acquired AdMeld and CRO of MySpace.

Asked why he's still taking on new jobs after a number of successful career stops, Mr. Barrett replied: "You ever try to play golf in 4 degree weather? It's really brutal, man."

He continued on a more serious note:

"I guess if there was no innovation, if there was no seismic changes occurring every several years, maybe it would be time to watch daytime TV. Right now, it's way to exciting and the opportunities are still too great."

Indeed, as Ad Age reported late last year, mobile advertising is expected to grow by over $5 billion dollars both this year and next.

Millennial Media's stock has vacillated rather dramatically over the past year, reaching a high of 14.66 and a low of 5.78. "If we were a railroad that would definitely be a bad sign. But we're a high growth company," said Mr. Palmieri, who will remain with the company as a paid advisor and explained his resignation from the board as a move that will provide "clarity of leadership."

Wall Street, for its part, seems to be a fan of Mr. Barrett's. Millennial's stock is up over 10% on the day.