Zorian Tytych, 18, got four As and has been given a place at Durham University while his father fights on the front line.
The teenager came to the UK to study prior to the outbreak of war and watched in horror as his family fled from his home city of Kyiv.
While studying at Cardiff Sixth Form College in Wales he volunteered as a translator to help Ukrainian refugees staying with host families in the capital.
After sitting his exams he signed up as a volunteer translator with the Armed Forces to help some of the 10,000 Ukrainian soldiers receiving training in the UK.
His father, a lawyer, signed up to fight for his country the day after the war began and is on active service stationed on the Belarus border.
“Before the war started my mother and father were lawyers,” Zorian said.
“Dad was on the Ukrainian committee for Judicial Reform, taking things up to the European Union level.
“He joined the military the day after the war started, signing up to the territorial defence and receiving basic training.
“He did this because he wanted to protect his home and support his country.
“My cousin is doing the same and is now based near Kherson where he is right in the thick of it and all the shelling.
“My uncle is currently in the recruitment process for joining the army.”
He added: “I cannot think too deeply about my father as it would drive me mad with worry, but I am very proud of him.
“I know he would feel it is a disgrace if he didn’t join the army.
“But I cannot think about it too much as it just makes me really concerned.”
Despite fearing for his family, Zorian was able to get an A grade in all four of his subjects – physics, maths, biology and chemistry.
His mother was forced to evacuate to Lviv in western Ukraine when gunfire drew too near to their home but she has since returned after Russian forces retreated from the city.
He said: “As well as studying for my A-levels at Cardiff Sixth Form College, I have been volunteering, visiting the homes of British people in Cardiff who have taken in Ukrainian refugees.
“I am helping these families by translating documents for them, helping them with day-to-day tasks and being a friend to them.
“They need someone they can communicate with.
“Britain now has 10,000 Ukrainian soldiers receiving training from the British Army here in the UK and they need translators and helpers.”
Zorian said that as he is unable to safely return home he will remain in the UK to study and stay with his godmother in London before heading to Durham in September.
College principal Gareth Collier said Zorian had been volunteering throughout his “very busy A-level revision period”.
He said one host family who Zorian worked with described him as “an example of an outstanding, selfless individual willing to help others where he can”.
Mr Collier added: “He has been an active member of the school community and we are delighted that he is able to continue his education here in the UK with these tremendous results.”