I very frequently see folks online say things like this: “Though technically speaking Archangel Michael is not a Saint [sic], sometimes this entity is venerated as one.”
I’m not linking to the source for that because my goal is not to single anyone out for being wrong. Thing is, this is not an uncommon misperception. It’s pretty easy to find multiple websites and blogs that say something to this effect – even those of folks who are otherwise pretty well-versed in folk religion and/or folk magic. If this were just a couple of blogs and not a pretty widespread point of confusion and error, I wouldn’t be going to the trouble to write about it.
I get that not everybody comes from a Catholic background. But if you’re going to write about saints in the context of hoodoo and folk religion, you should do your research before you make assertions. And if you do your research, you’ll see that in a hoodoo context, when you’re talking about saints, you’re nearly always talking about the definition of saint as used by the Catholic Church.
Some Protestant branches define a saint as basically anyone who is a Christian, a member of the body of Christ by virtue of being a member of the church. Others use the term to designate someone who is “born again” and/or someone who has been baptized (at least into their particular branch of Christianity). Some reserve the term mostly to refer to widely recognized holy figures, such as the biblical patriarchs or those who were martyred for their adherence to the Christian faith. The Church of Jesus Christ of Latter-Day Saints considers its members to be saints (but not the members of other churches).
But those are obviously not the operant definitions in traditional hoodoo. While the overwhelming majority of hoodoo practitioners historically have been Protestant Christians, there were always little geographical and cultural pockets of Catholicism (including folk Catholicism), and when rootworkers talk about working with saints, a quick survey of those saints and an understanding of the context in which they are petitioned make it clear that we’re talking about an understanding of sainthood from a Catholic perspective. We aren’t just talking about the biblical patriarchs and your very pious great aunt Emma, who is obviously a vibrant and committed member of the Body of Christ and brings the best potato salad in three states to the church picnic but is obviously not who you light a candle for on a few consecutive Tuesdays when you’re asking for her help.
Non-Catholic folks tend to think of saints as formerly living humans, maybe ones who led especially holy or exemplary lives, maybe performed a few miracles and now hang out in heaven doing various odd jobs for God and letting us bend their ears occasionally when we petition them. But that’s not how it works in Catholic ontology. According to the Roman Catholic Church, to put it as simply as possible, a saint is basically someone who’s in heaven, or to put it another way, if you’re in heaven, you’re a saint. But the actual fabric underlying all of this stuff is just a little more complicated. You can read more about it at the Catholic Encyclopedia, but it’s a concept called the communion of saints:
The communion of saints is the spiritual solidarity which binds together the faithful on earth, the souls in purgatory, and the saints in heaven in the organic unity of the same mystical body under Christ its head, and in a constant interchange of supernatural offices. The participants in that solidarity are called saints by reason of their destination and of their partaking of the fruits of the Redemption…
So you’re part of the communion of saints, the mystical body of Christ, even while you’re still living and even if you’re not quite living perfectly. This isn’t exactly the same thing as being an actual confirmed saint, but you have the potential, and as long as you can stay out of hell, you’ll keep that potential. After you undergo “purification” (or “remedial training” or “detention” or however you want to see Purgatory), then you’ll head to heaven to join the actual community of saints. In other words, as long as you don’t do something that goes down on the Big Permanent Record and lands you in hell, all roads lead to heaven eventually. So you are part of this spiritual economy and you can pray, receive blessings, ask forgiveness, ask a saint to intercede for you, say prayers for the souls of your ancestors, etc. More on this spiritual economy in a moment, but the key point now is that all of these spiritual actions have spiritual results, so things can always change. It ain’t over ’til it’s over.
To paraphrase from later on that same linked webpage, then, saints are basically those who are in fellowship with God the Father and Christ. St. Thomas Aquinas, the great Scholastic philosopher and foremost theologian of the Catholic Church, known as the Angelic Doctor and the Angel of the Schools , writes in Summa Theologiae III:8:4:
Where there is one body we must allow that there is one head. Now a multitude ordained to one end, with distinct acts and duties, may be metaphorically called one body. But it is manifest that both men and angels are ordained to one end, which is the glory of the Divine fruition. Hence the mystical body of the Church consists not only of men but of angels. Now of all this multitude Christ is the Head, since He is nearer God, and shares His gifts more fully, not only than man, but even than angels; and of His influence not only men but even angels partake, since it is written (Ephesians 1:20-22): that God the Father set “Him,” namely Christ, “on His right hand in the heavenly places, above all Principality and Power and Virtue and Dominion and every name that is named not only in this world, but also in that which is to come. And He hath subjected all things under His feet.” Therefore Christ is not only the Head of men, but of angels. Hence we read (Matthew 4:11) that “angels came and ministered to Him.”
So the angels, at least the ones who didn’t rebel, are members of the communion of saints, which the Catholic church characterizes in that linked article as “that reciprocal action of the saints, that corporate circulation of spiritual blessings through the members of the same family, that domesticity and saintly citizenship.” They are under Christ’s power and thus receive his grace, so they’re part of this same spiritual economy that the living and the dead are active participants in. (Yes, the dead, which is another big difference between Catholicism and Protestantism and is probably another blog post… but yes, your prayers can help your dead reprobate uncle Joe who’s doing time in Purgatory. And your saintly Grandmother Bosworth, who worked her fingers to the bone and never deserved any of the grief that Joe brought her and who is hanging out in heaven with the other saintly grandmothers, well, she can help you, too, with *her* prayers.)
And angels, some of whom Grandmother Bosworth is doubtless rubbing shoulders with at the right hand of God — or at least in a pastoral courtyard just cattycorner to the right arm of God’s comfy chair, but don’t nitpick Grandmother Bosworth! — can hear us and help us. They are part of this same system of reciprocity that extends beyond the borders of life and corporeality, the same spiritual economy in which we might petition a saint and promise a certain “payment” or offering in return, in which working with graveyard dirt or spirits of the dead is not seen as “disturbing their rest” at all. That idea is totally alien to a Catholic worldview. The dead aren’t gone and beyond our ability to interact with. They’re right here. Grandmother Bosworth still wants to help you.
And so with angels. They are our guardians on this earthly plane and they even serve as psychopomps when we’re leaving it. 
That’s not to say they’re all sweetness and light or they have the same tolerance for your bullshit that Grandmother Bosworth does. Don’t waste an angel’s time whining and don’t make the mistake of thinking they are all hanging around looking like Precious Moments figurines worrying about your love life or your chakras. There’s a reason angels who show up in the Bible often start off with “Don’t be afraid.” But in the Catholic conception of the communion of saints, angels are 100% active participants and on the same team. And they are absolutely saints.
So yes, St. Michael IS a saint. And an angel. At the same time. The angels who did not rebel are all members of the mystical body of the Church and the communion of saints. People who say otherwise have obviously not come up in this tradition – which is fine! Again, Catholic rootworkers have always been a minority. But they also just haven’t done their research before they opened their mouths, which is really not fine. But the bottom line is that St. Michael can be both a saint and an angel because the Roman Catholic definition of a saint is not the same as the kinda vague concept of sainthood that is floating around in culture more broadly.
And so this in turn should help you see how folk saints fit into all of this – figures who have *not* been formally recognized or canonized by the Catholic church but who are nonetheless venerated by the faithful and seen to have an ability and willingness to respond to the petitions or prayers of the faithful. That’s how there can be so many darned saints and the Catholic Church doesn’t even pretend that there’s a list anywhere of all of them — because the Church does not *make* saints or grant that status to people or entities. In beatification and canonization, the Church merely formally recognizes the status of sainthood that that person has already attained whether we knew about it or not, and outlines the proper observance of their veneration by the faithful. So there are tons of saints that aren’t formally recognized by the Church with their own feast day or series of statues or whatever. And among the forgotten virgin martyrs and the soldiers of Christ whose names we never knew, we also have figures of folkloric status, both human and not, who are also very active participants in their devotees’ lives: Santa Muerte, Jesus Malverde, Yevgeny Rodionov, Marie Laveau.
Maybe even your pious great aunt Emma one day. Patron saint of the perfect picnic potato salad.
 Yeah, did you catch that? Among his several venerable titles, St. Thomas Aquinas is referred to as an angel. Here’s a quick tidbit excerpted from an old children’s schoolbook and here’s a student’s prayer to St. Thomas as the Angel of the Schools. This epithet would need a whole separate blog post to properly unpack, and we’d have to start with etymology, and I can feel some of your eyes glazing over already lol, but please let all this serve for now to demonstrate the extent to which God’s creation, and by extension the various available modes and categories of being, are much more complex and dynamic and perhaps even unruly from a Catholic perspective than a non-Catholic might be prepared to appreciate without dropping some highly problematic assumptions and doing some serious digging. So don’t listen to ignorant people talking about the saints, not even if they’re quite well-informed on other aspects of magic or mysticism or religion. There are a lot of folks out there holding forth about saints and angels and who’ve set themselves up as experts who don’t actually know what the hell they’re talking about, not to put too fine a point on it.
 This has always been one of St. Michael’s preeminent roles, in fact. Here’s an 11th century prayer to St. Michael that is fairly typical of its ilk:
Therefore I beseech and entreat you, St Michael the Archangel, who knows those of the accepted souls to be received, find my soul worthy when it leaves my body and free it from the power of the enemy, so that it avoids the gates of hell and the ways of shadows and the lion and dragon who usually receive souls in hell and lead them to eternal torment. [Te ergo supplico et deprecer sancte michael archangele qui ad animas accepiendas accepisti postestatem ut animam meam suscipere digneris quando de corpere meo erit egressa et libera eam de potestate inimici ut pertransive possit portas infernorum et vias tenebrarum ut non se deponat leo vel draco qui conseutus est animas in inferno recipere et ad aeterna tormenta perducere.]
From Oxford Bodleian Library MS Douce 296, fol. 122v. Cited in Kathleen Openshaw, “The Battle between Christ and Satan in the Tiberius Psalter,” Journal of the Warburg and Courtauld Institutes 52:14-33