After returning to Poland, he fought in 1626 against the Swedes in the last phase of the Polish–Swedish War, where he took part in the battle of Gniew. His involvement in this conflict, which lasted till the Truce of Altmark in 1629, was rather limited, and he spent much time in other parts of the country. During that period and afterward, he lobbied for support of his candidature for the Polish throne, as his father, Sigismund, was getting more advanced in his age, and the succession to the Polish throne did not occur through inheritance but rather through the process of royal elections. While Władysław, and his father Sigismund, tried to ensure Władysław's election during Sigismund's life, this was not a popular option for the nobility, and it repeatedly failed, up to and including at the sejm of 1631. Sigismund suffered a sudden heart attack on 23 April 1632 and died in the morning hours of 30 April, forcing the issue to be taken up again.