I ask, because I know in the East, married men may be ordained, but may not marry after ordination. However, I recently found out that a former Byzantine Catholic priest converted to Orthodoxy and married.
The Orthodox position generally is that they don’t speculate on the validity of sacraments or orders outside their own communion. You will thus not find hard and fast rules regarding these issues in the same way we regard their orders or sacraments.
Thanks. So if a Catholic priest converted to Orthodoxy and wished to be an Orthodox priest, they would likely conduct their own ordination, so their would be no impediment to his marriage beforehand.
They might, or they might not
Depends on the jurisdiction / bishop. A Catholic priest may be re-ordained, or he may simply be received by vesting and a confession of faith. There is no hard and fast rule universal to Orthodoxy.
Exactly - the principle of economy would play a part as well.
There are all sorts of factors involved. Men may not marry after ordination, but in extraordinary cases, they can be laicized, in which case they can marry, but never be ordained again after being laicized.
On the question of validity, the issue can be complex. Orders outside of the Church per se are considered to lack the grace which is unique to the Church and so by akriveia (exactitude or strictness) they are said to be invalid. By economy, the grace of the Church can be provided without repeating the form or sign under which the sacrament is normally conferred; thus orders from outside of the Church can be regarded as valid, but only with respect to the acceptance of persons with such orders into the Church and not with respect to such orders in themselves.
With all of that being said, although it is perhaps possible to receive a priest from other confessions, allow him to marry, and then ordain him, in practice, this would be rare, even in places where receiving priests by ordination is the norm.
Which Church did he join? Are you sure it is canonical? I have a hard time believing a canonical bishop would allow that.