Owusu was appointed as a State Attorney in the Attorney-General's Department in March 1973.[4] After working in that capacity for three years, she was promoted to the rank of Senior State Attorney, Second- in-Command in 1976 and later elevated to the position of Principal State Attorney in 1983.[4][3]
On 19 September 1989 she was appointed to the Bench as a justice of the High Court. After a decade of service to the High Court bench she was appointed an Appeals Court judge in 1999.[4] She served in that capacity until 2008 when she was appointed as justice of the Supreme Court of Ghana. She retired in 2014.[4][3]
