Oh...kay. So, who's Alfred?- Stephanie Brown
"Gotta say, it's worth coming back to see you lose that British cool,"-Stephanie Brown to Alfred Pennyworth
Alfred, being close to Bruce and Tim, knew about Stephanie for some time before they actually met. He teased Tim about being interested in her (and overpowered by her) when the Spoiler and Robin first "met".
Stephanie first learned of Alfred's identity as Batman's butler in Robin #87, with the last panel of the issue having her ask, "Oh...kay. So, who's Alfred?" after Tim mentioned him while arguing with Batman.
Batman also told Alfred when he fired Stephanie as Spoiler. Alfred pondered that it was maybe for the best another young girl wasn't going to be lost to the vigilante game, and was nice enough to call Tim and tell him what had happened, and that he should go comfort Stephanie.
Alfred was there when Stephanie became Robin. He expressed disapproval at the notion, and asked Batman if he was just making her his sidekick in order to make Tim jealous. Batman did not respond.
In Robin #174, Stephanie, revealed never to have been dead, sees Alfred once again. He is so shocked, he drops his tray. Stephanie laughs, and tells him affectionately it was worth coming back to see him "lose his British cool." He is clearly pleased to see her alive.
Alfred resutured Stephanie's bullet wound in the Batcave in Robin #180 and Steph confided in him Tim had been using extreme tactics like the Scarecrow's fear gas, and thought to herself that she didn't know if it was good or bad.
Alfred also confirmed that Steph's bullet wound matched the bullets from The General's gun, when Tim called and asked.
In Bruce Wayne- The Road Home: Batgirl Bruce Wayne meets with Alfred in an alley. Alfred asks Bruce if he will let Steph continue to “do her thing,” (after Bruce returns, no one is sure if he will let Steph stay as Batgirl) to which Bruce says yes but he wants to keep a watchful eye on both her and Wendy, as they are daughters of criminals. Alfred defends Stephanie and tells Bruce blantantly that Steph never really needed to be tested, but Bruce defends his actions, saying that no, he didn’t need to test her, but she needed the test. Alfred also confronts Bruce about Cassandra Cain, the previous Batgirl, and why hasn’t he searched or even asked after her? Bruce states that he knows exactly where she is and that Tim Drake has been in contact with her. That if anything bad happened to Bruce, Cass knew what to do. Alfred wonders if part of that was giving Steph the cowl and Bruce says “It’s like I said, Alfred…because Stephanie needed the test….and everyone deserves a second chance.”
Learn more about Alfred here