BOSTON (AP) — On Beacon Hill, William Maurice ‘‘Mo’’ Cowan has been best known as the affable, bowtie-wearing private face of Gov. Deval Patrick’s administration, doling out legal advice as chief legal counsel and policy advice as chief of staff.
Now the North Carolina native is making the jump into the political spotlight.
On Wednesday, Patrick appointed Cowan, 43, to serve as interim senator to fill the seat being vacated by Democratic U.S. Sen. John Kerry, who is leaving to become the nation’s next secretary of state. Cowan will serve until a special election is held on June 25.
For Cowan, who will become the state’s second black U.S. Senator, the brief stint in the Capitol will mark the pinnacle of a rise through the state’s legal and political landscape, though he said it will not be a prelude to any kind of run for public office.
After graduating from Duke University and Northeastern University School of Law, Cowan launched a career as a lawyer.
From 1997 to 2009, Cowan practiced civil litigation at the Boston office of Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, eventually becoming partner. He also worked as a special assistant district attorney in Middlesex County.
Since 2009, Cowan has been an integral member of the Patrick administration.
‘‘Mo is a highly respected public citizen,’’ Patrick said as he introduced Cowan at a press conference Wednesday. ‘‘He has been a valued ally to me and to our work.’’
Lt. Gov. Timothy Murray said Cowan’s personal style also brought a touch of hipness to a building not known for its trendsetting ways.
‘‘He’s cool,’’ Murray said. ‘‘Tom Brady, George Clooney, James Bond, the president have nothing on Mo.’’
Cowan said his greatest inspiration was his mother, who was in North Carolina recovering from knee surgery Wednesday.
‘‘She’s a child of the segregated south, a single mother to my sisters and me after my father died when I was a teenager, a woman who did not have the opportunity to attend college,’’ Cowan said. ‘‘But my mother told me days like today were possible. If you work hard and treat people with respect there’s very little you cannot achieve.’’
Cowan said he first came to Massachusetts 22 years ago looking for opportunity and was rewarded — finding a career, marrying his wife Stacy and starting a family with their two sons Miles and Grant.
It’s also clear that Patrick, the state’s first black governor, saw echoes of his own life story in Cowan. Like Cowan, Patrick also ended up finding a home, a family and both private and political opportunities in Massachusetts after leaving Chicago as a teenager to attend a prep school in Milton.
Patrick called Cowan’s life story an ‘‘affirmation of the American Dream.’’
‘‘The commonwealth, and the country, is changing,’’ Patrick said. ‘‘The breadth of diversity of background and ethnicity and race is deeper and broader than ever and I have known for a long time and have believed for a long time that there is talent in every community.’’
One thing Patrick said he doesn’t share with Cowan is his sense of style.
‘‘I'm not that cool,’’ Patrick said.
Cowan opted for a necktie during the press conference. Patrick said his advisers urged Cowan to abandon his bow tie for his first outing as the state’s next senator.
‘‘It’s the only one of their judgments with which I disagreed,’’ Patrick joked.