An Anglophone, he joined the New Hebrides British National Service as a clerical officer in 1957 and spent almost 20 years in the District Administration.

[1] He was elected President (a ceremonial office) by the Parliament when Vanuatu gained independence in 1980.

He resigned in February 1984 while he was being prosecuted for a tax violation, but was reelected and restored to the presidency weeks later by the Parliament for a five-year term.

In December 1988, he attempted to dismiss the Prime Minister, Walter Lini,[2] and install a new government headed by his own nephew, Barak Sopé; the Supreme Court of Vanuatu overturned the President's decision the next day.

The Electoral College removed Sokomanu from office for gross misconduct in 1989.