Sarsa Dengel fought against the Ottomans, defeating regional ruler Bahr Negus Yeshaq and Adal Sultan Muhammad V. He also repelled the Turkish invaders in Debarwa and Hirgigo.

Despite his military successes, historians argue that his focus on northern campaigns instead of addressing the Oromo expansion in the south ultimately led to the decline of the Ethiopian Empire.

[7] When the Ottomans withdrew from Debarwa, the local ruler Yeshaq promptly seized the opportunity to occupy it and forge an alliance with the Turks.

Sarsa Dengel then seized the vast riches stored by the Turks in Debarwa and ordered the destruction of the mosque and the fort erected during the Ottoman occupation.

[11] The chronicler, who was greatly impressed by the Emperor's military victories exclaims: "Who among the kings of Ethiopia has defeated the Turkish army supplied with rifles and cannons?

"[12] Upon defeating the Turks, Sarsa Dengel then held his coronation at Aksum and in 1580 he departed from Tigray to conduct a campaign against the Beta Israel in Semien province.

[18] On his final campaign against the Oromo in Damot, his Chronicle records,[19] a group of monks tried to dissuade him from this expedition; failing that, they warned him not to eat fish from a certain river he would pass.

When Robert Ernest Cheesman visited the church in March 1933, he was shown a blue-and-white porcelain jar, which his entrails were brought from the place of his death.

[24] According to Professor Mordechai Abir, “the many historians who described Sersa Dangel as an able, heroic, and successful monarch completely distorted the truth.” He believes that Sarsa Dengel's obsession to consolidate his government in the Beta Israel provinces in the north instead of focusing his resources and attention in the south to stop the Oromo expansions was a turning point in Ethiopian history.

Silverbger further calls the Emperor a valiant warrior and refers to his time on the throne as "the 35 triumphant years" during which Sarsa Dengel scored several decisive victories over his various enemies.