Wooster first met Gil while Gil was living incognito as a student in Paris. On leaving Paris, Gil brought Wooster to Castle Wulfenbach with the promise of a job, revealing that he was the Wulfenbach heir. (Unbeknownst to Wooster, Gil was also keeping the close to hand and feeding him false information.) Wooster worked as Gil's manservant for quite some time, and the two seem to have developed a genuine affection for each other.
On learning that Agatha Heterodyne is not dead, Gil secretly sends Wooster to protect her. In a transformative display of Spark charisma, Gil Wooster's obedience, though he must reveal his knowledge of Wooster's occupation and orders to do so. A thoroughly cowed Wooster takes Gil's flyer to Sturmhalten, where he hooks up with Master Payne's Circus of Adventure, fights against Gil's father in the Battle of Sturmhalten, and narrowly avoids being killed by Bangladesh DuPree. Wooster Agatha to safety in England as Gil had commanded, but Agatha insists on going to Mechanicsburg instead. Only the Circus accepts Wooster's invitation.
Wooster meets Agatha in the Heterodyne Mountain Bunkers, or "The Sneaky Cave." Placed there by his superiors in the British spy network as punishment for cover blown, network exposed, target lost, Europa destabilized, and there are far worse punishments. He personally is not the reason for any of those events, but he was there and didn't prevent it. His new assignment as a disgraced British spy is to keep an eye on things near Mechanicsburg.
Time hasn't affected him much when he makes his first appearance after the time skip. He still has the same hairstyle, and —when not disguised— wears his clothes in the same style as when on Castle Wulfenbach. His skin tone is a bit darker, and if it wasn't for the name and hair color could be mistaken for Vanamonde von Mekkhan. His hair is also a bit disheveled, perhaps he just woke up on the wrong side of the bed.
He subsequently joins Agatha on her journey when she sets out for Paris in an attempt to find a way to free Mechanicsburg from the Baron-induced time-bubble, helps analyze Gil's mental condition (demonstrating his mastery of disguise) during events at the Corbettite Depot Fortress of St. Szpac, and then escorts her to England proper, chasing after the Smoke Knight Madwa Korel and the time-altering lamp in her possession. The attempt to capture Korel leads to the discovery of what is supposedly her dead body on her arriving submarine, with no sign of the Lantern. Wooster later takes Tarvek (and, unknowingly, an undercover Higgs) to meet with Agatha at her new digs in the dome of the Queen's Society, which is locked down in the midst of a murder investigation: during this sequence, it is noted that Wooster holds the rank of Commander and has clearance level 2-A, allowing him access to the dome. (And is in fact officially ordered to investigate said murders.) This is the first real evidence that someone besides himself has a high opinion of his work.
The murders are revealed to be part of a conspiracy on the part of the dome's resident Sparks to summon up an extradimensional visitor and tap into said entity's power; Wooster assists Agatha and Co, in successfully thwarting this scheme, but then an attempt is made to extract the copy of Lucrezia Mongfish from Agatha's mind. As Wooster deals with invading wasp-infected British troops, the removal effort goes badly, leading instead to Lucrezia taking control of Agatha's body, mastering the Spark, and attaining Queenhood. When confronted by an enlarged raging Lucrezia demanding his submission, Wooster stoically maintains his loyalty to Albia, and is
Unsurprisingly, Wooster is personally acquainted with his fellow British agents Hippocrates Brunel (whom he clearly ), Hadrian Rakethorn (again, ) and Trelawney Thorpe (whom he very much). After he dies, Trelawney shows that she had had feelings for him in return.
Ardsley Wooster is a card in The Works, where he's also Hero and Spy. Have some tea.
Possibly relevant outside information
Bertie Wooster is the name of a character in PG Wodehouse's Jeeves series, about a snarky valet. That Wooster was the employer, however, and far less "with it" than either this Wooster or his boss. Then again this Wooster performs the mission without real thought to prevent the later consequences, and is more of a spontaneous, in the moment spy.
His rank is likely a reference to James Bond, who also holds the rank of Commander in the Royal Navy Reserve. Additionally his command designation is "Royal Delta 00", which also could make him a 00 agent.