Adam Barrett's spell as caretaker manager began in perfect fashion on 5th October as The Lions defeated Leeds United 2-1 at The Den.
In a typically red-hot SE16 atmosphere, Jed Wallace and Tom Bradshaw were on target as the 10-man Whites were downed.
After the international break, it looked as though the momentum was to continue as Millwall found themselves 2-0 up at Griffin Park against Brentford, but a late collapse saw The Lions come away pointless, losing 3-2.
Bradshaw, who found the net in West London, kept up his scoring record with a brace in a 2-2 home draw with Cardiff City, before Ben Thompson became the first man to score in the Gary Rowett era on 26th October as The Lions defeated Stoke City 2-0 - Jed Wallace with the other goal.
Rowett took over shortly before the visit of The Potters, and one of his main tasks was improving the club's away form. However, despite a spirited performance at Reading on 2nd November, complete with a stunning solo Jed Wallace goal, Millwall were to lose 2-1.
Seven days later, though, Matt Smith's late, late header sent three sides of The Den into bedlam as The Lions overcame local rivals Charlton Athletic - and that was to spark a run of form, as Jed Wallace's sublime free-kick gave Millwall a long-overdue away win, this time at Swansea City, before draws at home to Wigan Athletic and away to Birmingham City ended November.
The final month of the year got underway with Aiden O'Brien's injury-time leveller restoring parity in a 2-2 draw with Nottingham Forest, before back-to-back away wins - at Bristol City and Derby County - put The Lions in a good position going into the Christmas period.
Millwall were to come crashing back down to earth on 21st December, though, as struggling Barnsley won 2-1 at The Den, before yet another Jed Wallace free-kick - one which was voted as The Lions' Goal of the Season - gained a point at Cardiff City on Boxing Day. O'Brien took advantage of Jayson Molumby's pressing to net the winner against Brentford to round off 2019.
The new year was just around the corner - could The Lions continue their rise up the League table?
Take a look at all the goals from Part Two of our Season Review below...