The phrase "although he regretted" is correct and usable in written English.
It can be used to introduce a contrast or concession in a sentence, typically when discussing feelings or actions that are in conflict with one another.
Example: "Although he regretted his decision, he knew it was the right choice for his future."
Alternatives: "even though he felt remorse" or "despite his regret".
He added that although he regretted the comment, he doubted he would apologize for it in a subsequent column.
Andrew Tyrie, the chairman of the commission, however, described the plans as "a step in the right direction" although he regretted the lack of the reserve power.
Petrit Selimi, an aspiring PDK deputy, retorts that although he regretted the fiddling, his party would have won the vote anyway.
Although he regretted his lifelong love affair with the weed, he always said his aim was to "stay fit enough to enjoy my vices".
The manager was lucky to have received this feedback in time to get his career back on track, although he regretted that he had waited for a negative review to ask basic questions about his leadership activities.
Although he regretted Russia's transformation from a constitutional monarchy into a republic, he accepted the post of minister of war and the navy (March 15) and tried briefly but unsuccessfully to restore discipline in the army.
Petrit Selimi, an aspiring PDK deputy, retorts that although he regrets the fiddling, his party would have won anyway.
Although he regrets the ever-diminishing number of independent record shops, the plight of the industry as a whole does not affect him.
Newton was kept pretty busy not being a photographer in Singapore, although he regrets failing to trap "the Bengal Tiger," a White Russian dancer with red hair.
It came to a point where a move up to Hull seemed the best choice – the four-and-a-half-year deal offering obvious monetary gain – although he regrets the manner of his exit from Fulham.
Although Netanyahu said he regretted that his appearance had been interpreted as political and thanked Obama for his help to Israel, many Democrats were unmollified.
