The 27-year-old earned his maiden cap in the Republic of Ireland's 2-1 friendly win over the USA at the Aviva Stadium.
Stevens, who left Fratton Park for Championship outfit Sheffield United last summer, replaced Shane Duffy in the 77th minute.
The full-back represented Ireland three times at under-21 level and is now also capped at senior level.
Stevens had previously told how Pompey was his last-chance saloon when he was handed his first international call-up in March.
He made 99 appearances for Paul Cook's Blues after joining from Aston Villa in 2015, scoring once, and was a key member of the League Two title-winning side last year.