Guy Oseary's entrepreneurial leadership and global vision includes the development and innovative business management of artist brands, (Madonna), producing films (vampire film trilogy Twilight), concert tours (Madonna's "Sticky & Sweet Tour” grossed 408 million dollars), management of three-time American League MVP Alex Rodriguez, advisor to the leading coconut water brand company (Vita Coco), and a joint venture partnership with Iconix Brand Group in the apparel industry.

At the age of 15, Guy Oseary began searching for and developing talent in Los Angeles while still in high school. Two years later, he joined what was to become Maverick Records as an A&R man and quickly rose through the ranks to become Chairman of the label. During Oseary's tenure, he guided Maverick to sales of over l00 million units globally including 33 million copies of the debut album of his young discovery Alanis Morrisette. Her "Jagged Little Pill" album would take home four Grammy Awards in l996, including Album of the Year, securing a spot for Maverick Records as one of the industry's leading boutique labels. During Oseary's tenure the label also released albums by Michelle Branch, Prodigy, Deftones and The Wreckers as well as soundtracks to "The Wedding Singer," "The Matrix," "Austin Powers," and Quentin Tarantino's films “Jackie Brown” and “Kill Bill.”

In 2005, Oseary became Madonna's manager following several years as the artist's business partner. Their collaboration in all aspects of Madonna's career included the release of multi platinum CDs and two recent worldwide concert tours. The 2006 "Confessions Tour" grossed $195 million and her 2008-2009 "Sticky & Sweet" Tour was the most successful tour by a solo artist in history with gross revenue of 408 million dollars. In 2007, Oseary negotiated a groundbreaking deal by partnering Madonna with Live Nation, the number one touring promotion company in the world. The unprecedented deal is valued at 120 million dollars.

As part of Maverick Films, Oseary executive produced the stunningly successful Twilight series. The latest installment, The Twilight Saga: Eclipse set a new record for the biggest midnight domestic opening in box office history. The three movies to date have grossed over l.7 billion dollars.

In 2009, his client, three-time American League MVP, NY Yankees third baseman, and baseball giant, Alex Rodriguez, won his first World Series Championship.

NBC's Last Call with Carson Daly, recently renewes for an eleventh season, is executive produced by Oseary along with NBC's New Year's Eve – also hosted by Daly.

Since 2004, Oseary has been a principal at the top entertainment management company, Untitled Entertainment (in partnership with Jason Weinberg and Stephanie Simon). The firm oversees a roster of clients including Hilary Swank, David Caruso, Penelope Cruz, Naomi Watts, Demi Moore, Ashton Kutcher, Lucy Liu, and Blake Lively amongst others.

In early 2010, Oseary became an adviser to Vita Coco, the coconut water brand company. He brought on board an investment group including Madonna, Demi Moore, Anthony Kiedis and Matthew McCounaghey. Vita Coco currently has a 70 percent market share for coconut water in the US with sales continuing to surge monthly.

Also in 2010, Oseary signed on as an advisor to Forbes proclaimed the company as "the fastest-growing company in web history." In April 2010, at just l7 months old, Groupon's valuation was l.35 billion dollars.

Last year, in partnership with Madonna, Oseary formed MDG Icon, a new joint venture with Iconix Brand Group which will focus on fashion and apparel projects. The first collection under MDG is a sunglass collection designed by Madonna in collaboration with designer duo Dolce and Gabbana. The first apparel collection, Material Girl, is a junior line designed by Madonna and her daughter sold exclusively in all Macy's stores.

Guy has an online investment fund with partner Ashton Kutcher, A-Grade.

Oseary has written two books and has had two photography books published.