He's on a whole lot of Prestige records as a sideman. He was kind of the house pianist. But his playing there is mostly restrained and in a different style than his post 1965 records with a few exceptions when he played with Dolphy. Mal moved more into free territory after 1968 though his music always remained pretty structured.
If you're looking for more interesting solo outings than the one you listened to:
The Opening (Clifford mentioned this one already)
Update (on Soul Note)
Meditations: Live at Dug (calmer than the Opening but with a lot of emotional depth)
And if you're looking for more of the rhythmic trio music you encountered at the last part of that cd:
Black Glory (on Enja with Jimmy Woode
Number Nineteen (like A.L.B.O.M. with excellent Dutch musicians and a little more exciting)
First Encounter (with Gary Peacock)
Blood and Guts (sounds like the title: heavy stuff and rhytmically very interesting)
Tokyo Bound (with two excellent Japanese musicians)
Free at Last (on ECM but not very ECMish, this is probably his best known)