William “Mo” Cowan, a 1994 grad­uate of North­eastern University’s School of Law, has been appointed by Gov­ernor Deval Patrick of Mass­a­chu­setts to serve as the state’s interim U.S. senator.

Cowan will replace U.S. Sen. John Kerry, who resigned after 29 years in the seat to become the nation’s sec­re­tary of state. Voters will choose Kerry’s per­ma­nent suc­cessor in a spe­cial elec­tion on June 25.

I pledge to people of Mass­a­chu­setts that during this interim period I will go to work every day with the needs and aspi­ra­tions of state’s cit­i­zens fore­most in my mind,” Cowan said in a Wednesday morning press con­fer­ence at the State House announcing his appoint­ment. “I know the cit­i­zens of Mass­a­chu­setts care about jobs, edu­ca­tion, and afford­able, high-​​quality health­care and I will work with those inter­ests in mind every day.”

Mo is a fan­tastic leader with a heart­felt com­mit­ment to public ser­vice,” said Joseph E. Aoun, pres­i­dent of North­eastern Uni­ver­sity. “He has that rare com­bi­na­tion of deep policy exper­tise and the ability to build excel­lent working rela­tion­ships with col­leagues. These tal­ents will serve him—and Massachusetts—well in the Senate.”

Cowan stepped down as Patrick’s chief of staff last November and had pre­vi­ously served as the governor’s chief legal counsel. He is also a former member of the lit­i­ga­tion sec­tion of the Boston-​​based law firm Mintz Levin Cohn Ferris Glosky, and Popeo, P.C. and the former pres­i­dent of the Mass­a­chu­setts Black Lawyers Association.

At the press con­fer­ence, Patrick called Cowan a trusted adviser, pro­fes­sional col­league, and a long­time friend. “Mo is a highly respected public cit­izen,” he said. “In every step, he has brought prepa­ra­tion, per­spec­tive, wisdom, sound judg­ment, and clarity of pur­pose. That has all earned him the respect, admi­ra­tion, and trust of people throughout government.”

Cowan’s pres­ti­gious career has been widely rec­og­nized. He has been named a “Top 5 per­cent Mass­a­chu­setts lit­i­gator” by Law and Pol­i­tics mag­a­zine and a “40 Under 40” busi­ness leader by the Boston Busi­ness Journal.

His North­eastern expe­ri­ence helped shape his career suc­cess. “North­eastern is what brought me to Mass­a­chu­setts, and I am thankful for the inspi­ra­tion, lessons, and real world expe­ri­ence I gained during the time I spent there,” Cowan said. “It is one of many pieces that helped bring me to where I am today.”

Of his first co-​​op as a judi­cial intern with the Hon­or­able Patti Saris of the Mass­a­chu­setts State Trial Court, Cowan once said, “Get­ting her real-​​time con­struc­tive crit­i­cism of my lawyering skills in their infancy was impor­tant in shaping the lawyer that I ulti­mately became. I was chal­lenged, I was pushed, and I was taught how to com­mu­ni­cate in writing as a lawyer.”

He also noted that his second co-​​op with North Car­olina Pris­oner Legal Ser­vices taught him an impor­tant lesson in lit­i­ga­tion. “It helped me realize that as an advo­cate you often have to place per­sonal feel­ings on the back burner to advo­cate for your client or to ensure that jus­tice is done.”