Growing environmental concern sparked renewed interest in the sustainable production of (bio)materials that can replace oil-derived goods. Polyhydroxyalkanoates (PHAs) are isotactic polymers that play a critical role in the central metabolism of producer bacteria, as they act as dynamic reservoirs of carbon and reducing equivalents. PHAs continue to attract industrial attention as a starting point towards renewable, biodegradable, biocompatible, and versatile thermoplastic and elastomeric materials. Pseudomonas species have been known for long as efficient biopolymer producers, especially for medium-chain-length PHAs. The surge of synthetic biology and metabolic engineering approaches in recent years now offers the possibility of exploiting the untapped potential of Pseudomonas-based cell factories for the production of tailored PHAs. In this article, we provide an overview of the metabolic and regulatory circuits that rule PHA accumulation in P. putida, and we discuss approaches leading to the biosynthesis of novel polymers (e.g., PHAs including non-biological chemical elements in their structures). The potential of novel PHAs to disrupt existing and future market segments is closer to realization than ever before. We conclude the review by pinpointing challenges that currently hinder the wide adoption of bio-based PHAs, and we propose strategies towards programmable polymer biosynthesis from alternative substrates in engineered P. putida strains. This article is protected by copyright. All rights reserved.