Cape Verde became independent from Portugal in 1975. In 1976, Melissa was named the first US ambassador to Cape Verde and Guinea-Bissau, which were ruled by the same political party, the Partido Africano da Independência da Guiné e Cabo Verde (PAIGC).
Melissa was sworn in as Ambassador in Washington in a ceremony attended by her family and authorities from the two countries. This would be her first of four swearing-ins, always at the State Department building and always with her family present. Shirley Temple Black, who used to be a famous actress when she was a child, was the official in charge of the swearing-in. Larry Eagleburger, the acting US Secretary of State, joked that, thanks to Melissa’s excellent swimming abilities, the government would save on travel between Cape Verde and Guinea-Bissau.

Cape Verde has enjoyed almost two hundred years of ties with the United States, principally the state of Massachusetts, dating back to the days when whaling ships would sail from Boston to the South Atlantic and stop at the islands for supplies and take on sailors. Because of the Cape Verdean diaspora in Massachussetts, Melissa was given an especially warm welcome.
“You would have enjoyed my presentation of credentials in Praia, the capital,” she wrote in a letter to her son Christopher. “An elegant black Mercedes picked me up (another black car for my deputy, Dean Curran), motorcycle escort, sirens, flags flying. As I arrived at the Presidential Palace, the American flag was being raised. I passed an honor guard carrying Kalashnikov machine guns and went up the stairs to the Ceremonial Room. My speech was carried on the radio. (…) I handed him a personal letter from [US President] Gerald Ford. To my surprise, [President Aristides Pereira] gave me an enormous armful of the most beautiful roses for my birthday (which it was)! This country is experiencing its eighth year of drought. It is so sad because the people work against incredible odds and now produce only five percent of their food requirements. (…) The roses astounded me because the drought conditions simply don’t allow for rose-growing. But yesterday I found out where they came from – deep in the center of the island of Santiago there is a valley called São Jorge which is high up and amazingly lush. It is there that the roses are grown.”

The Ambassador’s first “office” was a park bench. Then the embassy was set up in a building.
About a month later, when Christopher visited her, they spent Christmas on the island of Brava, one of the most remote in the archipelago, at the home of Padre Pio Olivio Gottin, an Italian priest who lived many years on that island. On Christmas Eve, the two of them were invited visit several families, all of them living in homes with furniture and clocks from Massachussetts. On Christmas Day, Padre Pio said Mass for the two and a small group of nuns. To this day, Christopher has a wooden pencil-holder given by the priest.
A few months after arriving in both countries, she was invited in February 1977 to go to Lagos, Nigeria, and meet Andrew Young, who had been named by President Jimmy Carter as ambassador to the UN. Young invited her to work with him at the US mission to the UN (USUN), to be the ambassador to the UN Economic and Social Council (ECOSOC). “I told him that I thought it was dreadful to run off from my post after having just arrived,” she wrote years later. “We had just started the important negotiations of a USAID (the US aid agency) agreement with each country – Cape Verde and Guinea-Bissau. (…) I was invited to every event Andy had in Lagos – lunches, speeches, meetings and dinners. The night before I was to fly back home, I talked to Andy again and told him I would like to change my mind and work with him. But that first I had to conclude some important business with the two little countries I was accredited to. Andy said ‘Take all the time you need. The job is yours’.”
In mid-1977, the family moved to New York.